| Message ID | 20241106193413.1730413-1-quic_wcheng@quicinc.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce QC USB SND audio offloading support | expand |
Hi, On 11/6/2024 11:33 AM, Wesley Cheng wrote: > Requesting to see if we can get some Acked-By tags, and merge on usb-next. Are there any more clarifications that I can help with to get this series going? I know its been a long time coming, so folks may have lost context, but if there are any points that might be blocking the series from getting merged, please let me know. Thanks Wesley Cheng > Several Qualcomm based chipsets can support USB audio offloading to a > dedicated audio DSP, which can take over issuing transfers to the USB > host controller. The intention is to reduce the load on the main > processors in the SoC, and allow them to be placed into lower power modes. > There are several parts to this design: > 1. Adding ASoC binding layer > 2. Create a USB backend for Q6DSP > 3. Introduce XHCI interrupter support > 4. Create vendor ops for the USB SND driver > > USB | ASoC > -------------------------------------------------------------------- > | _________________________ > | |sm8250 platform card | > | |_________________________| > | | | > | ___V____ ____V____ > | |Q6USB | |Q6AFE | > | |"codec" | |"cpu" | > | |________| |_________| > | ^ ^ ^ > | | |________| > | ___V____ | > | |SOC-USB | | > ________ ________ | | | > |USB SND |<--->|QC offld|<------------>|________| | > |(card.c)| | |<---------- | > |________| |________|___ | | | > ^ ^ | | | ____________V_________ > | | | | | |APR/GLINK | > __ V_______________V_____ | | | |______________________| > |USB SND (endpoint.c) | | | | ^ > |_________________________| | | | | > ^ | | | ___________V___________ > | | | |->|audio DSP | > ___________V_____________ | | |_______________________| > |XHCI HCD |<- | > |_________________________| | > > > Adding ASoC binding layer > ========================= > soc-usb: Intention is to treat a USB port similar to a headphone jack. > The port is always present on the device, but cable/pin status can be > enabled/disabled. Expose mechanisms for USB backend ASoC drivers to > communicate with USB SND. > > Create a USB backend for Q6DSP > ============================== > q6usb: Basic backend driver that will be responsible for maintaining the > resources needed to initiate a playback stream using the Q6DSP. Will > be the entity that checks to make sure the connected USB audio device > supports the requested PCM format. If it does not, the PCM open call will > fail, and userspace ALSA can take action accordingly. > > Introduce XHCI interrupter support > ================================== > XHCI HCD supports multiple interrupters, which allows for events to be routed > to different event rings. This is determined by "Interrupter Target" field > specified in Section "6.4.1.1 Normal TRB" of the XHCI specification. > > Events in the offloading case will be routed to an event ring that is assigned > to the audio DSP. > > Create vendor ops for the USB SND driver > ======================================== > qc_audio_offload: This particular driver has several components associated > with it: > - QMI stream request handler > - XHCI interrupter and resource management > - audio DSP memory management > > When the audio DSP wants to enable a playback stream, the request is first > received by the ASoC platform sound card. Depending on the selected route, > ASoC will bring up the individual DAIs in the path. The Q6USB backend DAI > will send an AFE port start command (with enabling the USB playback path), and > the audio DSP will handle the request accordingly. > > Part of the AFE USB port start handling will have an exchange of control > messages using the QMI protocol. The qc_audio_offload driver will populate the > buffer information: > - Event ring base address > - EP transfer ring base address > > and pass it along to the audio DSP. All endpoint management will now be handed > over to the DSP, and the main processor is not involved in transfers. > > Overall, implementing this feature will still expose separate sound card and PCM > devices for both the platform card and USB audio device: > 0 [SM8250MTPWCD938]: sm8250 - SM8250-MTP-WCD9380-WSA8810-VA-D > SM8250-MTP-WCD9380-WSA8810-VA-DMIC > 1 [Audio ]: USB-Audio - USB Audio > Generic USB Audio at usb-xhci-hcd.1.auto-1.4, high speed > > This is to ensure that userspace ALSA entities can decide which route to take > when executing the audio playback. In the above, if card#1 is selected, then > USB audio data will take the legacy path over the USB PCM drivers, etc... > > The current limitation is that the latest USB audio device that is identified > will be automatically selected by the Q6USB BE DAI for offloading. Future > patches can be added to possibly add for more flexibility, but until the userpace > applications can be better defined, having these mechanisms will complicate the > overall implementation. > > USB offload Kcontrols > ===================== > Part of the vendor offload package will have a mixer driver associated with it > (mixer_usb_offload.c). This entity will be responsible for coordinating with > SOC USB and the Q6USB backend DAI to fetch information about the sound card > and PCM device indices associated with the offload path. The logic is done > based on the current implementation of how paths are controlled within the QC > ASoC implementation. > > QC ASoC Q6Routing > ----------------- > Within the Q6 ASOC design, the registered ASoC platform card will expose a set > of kcontrols for enabling the BE DAI links to the FE DAI link. For example: > > tinymix -D 0 contents > Number of controls: 1033 > ctl type num name value > ... > 1025 BOOL 1 USB Mixer MultiMedia1 Off > 1026 BOOL 1 USB Mixer MultiMedia2 Off > 1027 BOOL 1 USB Mixer MultiMedia3 Off > 1028 BOOL 1 USB Mixer MultiMedia4 Off > 1029 BOOL 1 USB Mixer MultiMedia5 Off > 1030 BOOL 1 USB Mixer MultiMedia6 Off > 1031 BOOL 1 USB Mixer MultiMedia7 Off > 1032 BOOL 1 USB Mixer MultiMedia8 Off > > Each of these kcontrols will enable the USB BE DAI link (q6usb) to be connected > to a FE DAI link (q6asm). Since each of these controls are DAPM widgets, when > it is enabled, the DAPM widget's "connect" flag is updated accordingly. > > USB Offload Mapping > ------------------- > Based on the Q6routing, the USB BE DAI link can determine which sound card and > PCM device is enabled for offloading. Fetching the ASoC platform sound card's > information is fairly straightforward, and the bulk of the work goes to finding > the corresponding PCM device index. As mentioned above, the USB BE DAI can > traverse the DAPM widgets to find the DAPM path that is related to the control > for the "USB Mixer." Based on which "USB Mixer" is enabled, it can find the > corresponding DAPM widget associated w/ the FE DAI link (Multimedia*). From there > it can find the PCM device created for the Multimedia* stream. > > Only one BE DAI link can be enabled per FE DAI. For example, if the HDMI path is > enabled for Multimedia1, the USB Mixer will be disabled and switched over. > > Examples of kcontrol > -------------------- > tinymix -D 0 contents > Number of controls: 1033 > ctl type num name > ... > 1025 BOOL 1 USB Mixer MultiMedia1 Off > 1026 BOOL 1 USB Mixer MultiMedia2 On > 1027 BOOL 1 USB Mixer MultiMedia3 Off > 1028 BOOL 1 USB Mixer MultiMedia4 Off > 1029 BOOL 1 USB Mixer MultiMedia5 Off > 1030 BOOL 1 USB Mixer MultiMedia6 Off > 1031 BOOL 1 USB Mixer MultiMedia7 Off > 1032 BOOL 1 USB Mixer MultiMedia8 Off > > tinymix -D 2 contents > Number of controls: 7 > ctl type num name value > 0 INT 2 Playback Channel Map 0, 0 (range 0->36) > 1 BOOL 2 MDR-1ADAC Playback Switch On, On > 2 BOOL 1 MDR-1ADAC Playback Switch On > 3 INT 2 MDR-1ADAC Playback Volume 127, 127 (range 0->127) > 4 INT 1 MDR-1ADAC Playback Volume 127 (range 0->127) > 5 BOOL 1 Sony Internal Clock Validity On > 6 INT 2 USB Offload Playback Route PCM#0 0, 1 (range -1->255) > > The example highlights that the userspace/application can utilize the offload path > for the USB device on card#0 PCM device#1. > > When dealing with multiple USB audio devices, only the latest USB device identified > is going to be selected for offload capable. > > tinymix -D 1 contents > Number of controls: 9 > ctl type num name value > 0 INT 2 Capture Channel Map 0, 0 (range 0->36) > 1 INT 2 Playback Channel Map 0, 0 (range 0->36) > 2 BOOL 1 Headset Capture Switch On > 3 INT 1 Headset Capture Volume 1 (range 0->4) > 4 BOOL 1 Sidetone Playback Switch On > 5 INT 1 Sidetone Playback Volume 4096 (range 0->8192) > 6 BOOL 1 Headset Playback Switch On > 7 INT 2 Headset Playback Volume 20, 20 (range 0->24) > 8 INT 2 USB Offload Playback Route PCM#0 -1, -1 (range -1->255) > > "-1, -1" shows that this device has no route to the offload path. > > This feature was validated using: > - tinymix: set/enable the multimedia path to route to USB backend > - tinyplay: issue playback on platform card > > Changelog > -------------------------------------------- > Changes in v30: > - Rebased to usb-next tip > - Renamed the xhci-sideband driver to xhci-sec-intr to avoid confusion with the xHCI > audio sideband feature mentioned within the spec. > - Squashed the xhci-sec-intr change to set IMOD for secondary interrupters into the main > patch that introduces the overall driver. > > Changes in v29: > - Fixed some phrases/wording within the SOC USB documentation, and also added an output > with aplay -l for the example output. > - Fixed allocated string buffer for creating the USB SND offload mixer, and added > a PCM index check to ensure that the pcm index is less than the expected number. > - Added a complement enable jack call if USB backend DAI link drivers need access > to it. > > Changes in v28: > - Updated comments and commit log in the stop endpoint sync patch. Clarified that > the default stop endpoint completion routine won't fully run as expected since it > has a completion associated w/ the command. > - Added a null check for sb->xhci within xhci_sideband_create_interrupter(). This > is to just ensure that caller has registered sideband before calling create > interrupter. > > Changes in v27: > - Added some comments and notes about the offload design. Enforcing the q6routing > to only allow one USB mixer (PCM device) to be enabled at a time. > - Modified SND_JACK_USB notifications for all USB audio offloadable devices plugged > in > - Rebased on latest XHCI secondary interrupter IMOD changes upstream. Modified the > change in this series to allow for XHCI sideband to set the IMOD for sideband > clients. > - Updated documentation on how USB SND kcontrols are involved in the overall design. > - Remove mutex locking from suspend/resume platform ops, as USB core ensures that the > interface and device are in the RPM_ACTIVE state while disconnect is handled. > > Changes in v26: > - Cleaned up drivers based on errors from checkpatch > - Fixed several typos using codespell > - Removed any vendor specific notation from USB SND offload mixer patch > > Changes in v25: > - Cleanups on typos mentioned within the xHCI layers > - Modified the xHCI interrupter search if clients specify interrupter index > - Moved mixer_usb_offload into its own module, so that other vendor offload USB > modules can utilize it also. > - Added support for USB audio devices that may have multiple PCM streams, as > previous implementation only assumed a single PCM device. SOC USB will be > able to handle an array of PCM indexes supported by the USB audio device. > - Added some additional checks in the QC USB offload driver to check that device > has at least one playback stream before allowing to bind > - Reordered DT bindings to fix the error found by Rob's bot. The patch that > added USB_RX was after the example was updated. > - Updated comments within SOC USB to clarify terminology and to keep it consistent > - Added SND_USB_JACK type for notifying of USB device audio connections > > Changes in v24: > - Simplified the kcontrols involved in determining how to utilize the offload > path. > - There is one kcontrol registered to each USB audio device that will > output which card/pcm device it is mapped to for the offload route. > - Removed kcontrols to track offload status and device selection. > - Default to last USB audio device plugged in as offload capable. > - kcontrol will reside on USB SND device. > - Reworked the tracking of connected USB devices from the Q6USB BE DAI link. > Previously, it was convoluted by doing it over an array, but moved to using > a list made it much simpler. Logic is still unchanged in that the last USB > headset plugged in will be selected for offloading. > - Updated the USB SOC RST documentation accordingly with new kcontrol updates. > - Added logic to fetch mapped ASoC card and pcm device index that the offload > path is mapped to for the USB SND kcontrol (for offload route). > - Re-ordered series to hopefully make reviews more readable by combining > patches based on the layer modified (ie QC ASoC, ASoC, USB sound, and USB XHCI). > > Changes in v23: > - Added MODULE_DESCRIPTION() fields to drivers that needed it. > > Changes in v22: > - Removed components tag for the ASoC platform card, as the USB SND kcontrol for > notifying userspace of offload capable card achieves similar results. > - Due to the above, had to remove the review-by tag for the RST documentation, > as changes were made to remove the components tag section. > - Took in feedback to make the SOC USB add/remove ports void. > - Fixed an issue w/ the USB SND kcontrol management for devices that have multi > UAC interfaces. (would attempt to create the kcontrol more than once) > - Modified SOC USB card and PCM index select to be based off the num_supported > streams that is specified by the USB BE DAI. > - Modified comments on selecting the latest USB headset for offloading. > > Changes in v21: > - Added an offload jack disable path from the ASoC platform driver and SOC USB. > - Refactored some of the existing SOC USB context look up APIs and created some > new helpers to search for the USB context. > - Renamed snd_soc_usb_find_format to snd_soc_usb_find_supported_format > - Removed some XHCI sideband calls that would allow clients to actually enable > the IRQ line associated w/ the secondary interrupter. This is removed because > there are other dependencies that are required for that to happen, which are not > covered as part of this series, and to avoid confusion. > - Due to the above, removed the need to export IMOD setting, and enable/disable > interrupter APIs. > > Changes in v20: > - Fixed up some formatting changes pointed out in the usb.rst > - Added SB null check during XHCI sideband unregister in case caller passes > improper argument (xhci_sideband_unregister()) > > Changes in v19: > - Rebased to usb-next to account for some new changes in dependent drivers. > > Changes in v18: > - Rebased to usb-next, which merged in part of the series. Removed these patches. > - Reworked Kconfigs for the ASoC USB related components from QCOM Q6DSP drivers > to keep dependencies in place for SoC USB and USB SND. > - Removed the repurposing of the stop ep sync API into existing XHCI operations. > This will be solely used by the XHCI sideband for now. > > Changes in v17: > - Fixed an issue where one patch was squashed into another. > - Re-added some kconfig checks for helpers exposed in USB SND for the soc usb > driver, after running different kconfigs. > > Changes in v16: > - Modified some code layer dependencies so that soc usb can be split as a separate > module. > - Split the kcontrols from ASoC QCOM common layer into a separate driver > - Reworked SOC USB kcontrols for controlling card + pcm offload routing and status > so that there are individual controls for card and pcm devices. > - Added a kcontrol remove API in SOC USB to remove the controls on the fly. This > required to add some kcontrol management to SOC USB. > - Removed the disconnect work and workqueue for the QC USB offload as it is not > required, since QMI interface driver ensures events are handled in its own WQ. > > Changes in v15: > - Removed some already merged XHCI changes > - Separated SOC USB driver from being always compiled into SOC core. Now > configurable from kconfig. > - Fixed up ASoC kcontrol naming to fit guidelines. > - Removed some unnecessary dummy ifdefs. > - Moved usb snd offload capable kcontrol to be initialized by the platform offloading > driver. > > Changes in v14: > - Cleaned up some USB SND related feedback: > - Renamed SNDUSB OFFLD playback available --> USB offload capable card > - Fixed locking while checking if stream is in use > - Replaced some mutex pairs with guard(mutex) > > Changes in v13: > - Pulled in secondary/primary interrupter rework from Mathias from: > https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/drivers/usb/host?h=fix_eventhandling > - Did some cleanup and commit message updates, and tested on current code base. > - Added mutex locking to xhci sideband to help prevent any race conditions, esp. for when accessing shared > references. > - Addressed concerns from Hillf about gfp_flags and locking used in qc_usb_audio_offload. > - Rebased onto usb-next > > Changes in v12: > - Updated copyright year to 2024. Happy new years! > - Fixed newline format on mixer offload driver. > > Changes in v11: > - Modified QMI format structures to be const > > Changes in v10: > - Added new mixer for exposing kcontrol for sound card created by USB SND. This > allows for applications to know which platform sound card has offload support. > Will return the card number. > - Broke down and cleaned up some functions/APIs within qc_audio_offload driver. > - Exported xhci_initialize_ring_info(), and modified XHCI makefile to allow for > the XHCI sideband to exist as a module. > - Reworked the jack registration and moved it to the QCOM platform card driver, > ie sm8250. > - Added an SOC USB API to fetch a standard component tag that can be appended to > the platform sound card. Added this tag to sm8250 if any USB path exists within > the DT node. > - Moved kcontrols that existed in the Q6USB driver, and made it a bit more generic, > so that naming can be standardized across solutions. SOC USB is now responsible > for creation of these kcontrols. > - Added a SOC USB RST document explaining some code flows and implementation details > so that other vendors can utilize the framework. > - Addressed a case where USB device connection events are lost if usb offload driver > (qc_audio_offload) is not probed when everything else has been initialized, ie > USB SND, SOC USB and ASoC sound card. Add a rediscover device call during module > init, to ensure that connection events will be propagated. > - Rebased to usb-next. > > Changes in v9: > - Fixed the dt binding check issue with regards to num-hc-interrupters. > > Changes in v8: > - Cleaned up snd_soc_usb_find_priv_data() based on Mark's feedback. Removed some of > the duplicate looping code that was present on previous patches. Also renamed the API. > - Integrated Mathias' suggestions on his new sideband changes: > https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters > - Addressed some of Mathias' fixme tags, such as: > - Resetting transfer ring dequeue/enqueue pointers > - Issuing stop endpoint command during ep removal > - Reset ERDP properly to first segment ring during interrupter removal. (this is currently > just being cleared to 0, but should be pointing to a valid segment if controller is still > running. > > Changes in v7: > - Fixed dt check error for q6usb bindings > - Updated q6usb property from qcom,usb-audio-intr-num --> qcom,usb-audio-intr-idx > - Removed separate DWC3 HC interrupters num property, and place limits to XHCI one. > - Modified xhci_ring_to_sgtable() to use assigned IOVA/DMA address to fetch pages, as > it is not ensured event ring allocated is always done in the vmalloc range. > > Changes in v6: > - Fixed limits and description on several DT bindings (XHCI and Q6USB) > - Fixed patch subjects to follow other ALSA/ASoC notations. > > USB SND > - Addressed devices which expose multiple audio (UAC) interfaces. These devices will > create a single USB sound card with multiple audio streams, and receive multiple > interface probe routines. QC offload was not properly considering cases with multiple > probe calls. > - Renamed offload module name and kconfig to fit within the SND domain. > - Renamed attach/detach endpoint API to keep the hw_params notation. > > Changes in v5: > - Removed some unnecessary files that were included > - Fixed some typos mentioned > - Addressed dt-binding issues and added hc-interrupters definition to usb-xhci.yaml > > XHCI: > - Moved secondary skip events API to xhci-ring and updated implementation > - Utilized existing XHCI APIs, such as inc_deq and xhci_update_erst_dequeue() > > USB SND > - Renamed and reworked the APIs in "sound: usb: Export USB SND APIs for modules" patch to > include suggestions to utilize snd_usb_hw_params/free and to avoid generic naming. > - Added a resume_cb() op for completion sake. > - Addressed some locking concerns with regards to when registering for platform hooks. > - Added routine to disconnect all offloaded devices during module unbind. > > ASoC > - Replaced individual PCM parameter arguments in snd_soc_usb_connect() with new > snd_soc_usb_device structure to pass along PCM info. > - Modified snd_jack set report to notify HEADPHONE event, as we do not support record path. > > Changes in v4: > - Rebased to xhci/for-usb-next > - Addressed some dt-bindings comments > > XHCI: > - Pulled in latest changes from Mathias' feature_interrupters branch: > https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters > > - Fixed commit text and signage for the XHCI sideband/interrupter related changes > - Added some logic to address the FIXME tags mentioned throughout the commits, such > as handling multi segment rings and building the SGT, locking concerns, and ep > cleanup operations. > - Removed some fixme tags for conditions that may not be needed/addressed. > - Repurposed the new endpoint stop sync API to be utilized in other places. > - Fixed potential compile issue if XHCI sideband config is not defined. > > ASoC: > - Added sound jack control into the Q6USB driver. Allows for userspsace to know when > an offload capable device is connected. > > USB SND: > - Avoided exporting _snd_pcm_hw_param_set based on Takashi's recommendation. > - Split USB QMI packet header definitions into a separate commit. This is used to > properly allow the QMI interface driver to parse and route QMI packets accordingly > - Added a "depends on" entry when enabling QC audio offload to avoid compile time > issues. > > Changes in v3: > - Changed prefix from RFC to PATCH > - Rebased entire series to usb-next > - Updated copyright years > > XHCI: > - Rebased changes on top of XHCI changes merged into usb-next, and only added > changes that were still under discussion. > - Added change to read in the "num-hc-interrupters" device property. > > ASoC: > - qusb6 USB backend > - Incorporated suggestions to fetch iommu information with existing APIs > - Added two new sound kcontrols to fetch offload status and offload device > selection. > - offload status - will return the card and pcm device in use > tinymix -D 0 get 1 --> 1, 0 (offload in progress on card#1 pcm#0) > > - device selection - set the card and pcm device to enable offload on. Ex.: > tinymix -D 0 set 1 2 0 --> sets offload on card#2 pcm#0 > (this should be the USB card) > > USB SND: > - Fixed up some locking related concerns for registering platform ops. > - Moved callbacks under the register_mutex, so that > - Modified APIs to properly pass more information about the USB SND device, so > that the Q6USB backend can build a device list/map, in order to monitor offload > status and device selection. > > Changes in v2: > > XHCI: > - Replaced XHCI and HCD changes with Mathias' XHCI interrupter changes > in his tree: > https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters > > Adjustments made to Mathias' changes: > - Created xhci-intr.h to export/expose interrupter APIs versus exposing xhci.h. > Moved dependent structures to this file as well. (so clients can parse out > information from "struct xhci_interrupter") > - Added some basic locking when requesting interrupters. > - Fixed up some sanity checks. > - Removed clearing of the ERSTBA during freeing of the interrupter. (pending > issue where SMMU fault occurs if DMA addr returned is 64b - TODO) > > - Clean up pending events in the XHCI secondary interrupter. While testing USB > bus suspend, it was seen that on bus resume, the xHCI HC would run into a command > timeout. > - Added offloading APIs to xHCI to fetch transfer and event ring information. > > ASoC: > - Modified soc-usb to allow for multiple USB port additions. For this to work, > the USB offload driver has to have a reference to the USB backend by adding > a "usb-soc-be" DT entry to the device saved into XHCI sysdev. > - Created separate dt-bindings for defining USB_RX port. > - Increased APR timeout to accommodate the situation where the AFE port start > command could be delayed due to having to issue a USB bus resume while > handling the QMI stream start command. > > Mathias Nyman (1): > xhci: sec-intr: add initial api to register a secondary interrupter > entity > > Wesley Cheng (29): > usb: host: xhci: Repurpose event handler for skipping interrupter > events > usb: host: xhci-mem: Cleanup pending secondary event ring events > usb: host: xhci-mem: Allow for interrupter clients to choose specific > index > usb: host: xhci-plat: Set XHCI max interrupters if property is present > usb: dwc3: Specify maximum number of XHCI interrupters > ALSA: Add USB audio device jack type > ALSA: usb-audio: Export USB SND APIs for modules > ALSA: usb-audio: Check for support for requested audio format > ALSA: usb-audio: Save UAC sample size information > ALSA: usb-audio: Prevent starting of audio stream if in use > ASoC: Add SOC USB APIs for adding an USB backend > ASoC: usb: Add PCM format check API for USB backend > ASoC: usb: Create SOC USB SND jack kcontrol > ASoC: usb: Fetch ASoC card and pcm device information > ASoC: doc: Add documentation for SOC USB > ASoC: dt-bindings: qcom,q6dsp-lpass-ports: Add USB_RX port > ASoC: dt-bindings: Update example for enabling USB offload on SM8250 > ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp > ASoC: qcom: qdsp6: q6afe: Increase APR timeout > ASoC: qcom: qdsp6: Add USB backend ASoC driver for Q6 > ASoC: qcom: qdsp6: Add headphone jack for offload connection status > ASoC: qcom: qdsp6: Fetch USB offload mapped card and PCM device > ALSA: usb-audio: Introduce USB SND platform op callbacks > ALSA: usb-audio: qcom: Add USB QMI definitions > ALSA: usb-audio: qcom: Introduce QC USB SND offloading support > ALSA: usb-audio: qcom: Don't allow USB offload path if PCM device is > in use > ALSA: usb-audio: Add USB offload route kcontrol > ALSA: usb-audio: Allow for rediscovery of connected USB SND devices > ASoC: usb: Rediscover USB SND devices on USB port add > > .../bindings/sound/qcom,sm8250.yaml | 15 + > Documentation/sound/soc/index.rst | 1 + > Documentation/sound/soc/usb.rst | 491 ++++ > drivers/usb/dwc3/core.c | 12 + > drivers/usb/dwc3/core.h | 2 + > drivers/usb/dwc3/host.c | 3 + > drivers/usb/host/Kconfig | 11 + > drivers/usb/host/Makefile | 2 + > drivers/usb/host/xhci-mem.c | 31 +- > drivers/usb/host/xhci-plat.c | 2 + > drivers/usb/host/xhci-ring.c | 54 +- > drivers/usb/host/xhci-sec-intr.c | 439 ++++ > drivers/usb/host/xhci.c | 2 +- > drivers/usb/host/xhci.h | 14 +- > .../sound/qcom,q6dsp-lpass-ports.h | 1 + > include/linux/mod_devicetable.h | 2 +- > include/linux/usb/xhci-sec-intr.h | 70 + > include/sound/jack.h | 4 +- > include/sound/q6usboffload.h | 20 + > include/sound/soc-usb.h | 147 ++ > include/uapi/linux/input-event-codes.h | 3 +- > sound/core/jack.c | 6 +- > sound/soc/Kconfig | 10 + > sound/soc/Makefile | 2 + > sound/soc/qcom/Kconfig | 15 + > sound/soc/qcom/Makefile | 2 + > sound/soc/qcom/qdsp6/Makefile | 1 + > sound/soc/qcom/qdsp6/q6afe-dai.c | 60 + > sound/soc/qcom/qdsp6/q6afe.c | 194 +- > sound/soc/qcom/qdsp6/q6afe.h | 36 +- > sound/soc/qcom/qdsp6/q6dsp-lpass-ports.c | 23 + > sound/soc/qcom/qdsp6/q6dsp-lpass-ports.h | 1 + > sound/soc/qcom/qdsp6/q6routing.c | 32 +- > sound/soc/qcom/qdsp6/q6usb.c | 391 ++++ > sound/soc/qcom/sm8250.c | 24 +- > sound/soc/qcom/usb_offload_utils.c | 56 + > sound/soc/qcom/usb_offload_utils.h | 30 + > sound/soc/soc-usb.c | 369 +++ > sound/usb/Kconfig | 25 + > sound/usb/Makefile | 4 +- > sound/usb/card.c | 106 + > sound/usb/card.h | 17 + > sound/usb/endpoint.c | 1 + > sound/usb/format.c | 1 + > sound/usb/helper.c | 1 + > sound/usb/mixer_usb_offload.c | 102 + > sound/usb/mixer_usb_offload.h | 17 + > sound/usb/pcm.c | 104 +- > sound/usb/pcm.h | 11 + > sound/usb/qcom/Makefile | 2 + > sound/usb/qcom/qc_audio_offload.c | 1974 +++++++++++++++++ > sound/usb/qcom/usb_audio_qmi_v01.c | 863 +++++++ > sound/usb/qcom/usb_audio_qmi_v01.h | 164 ++ > 53 files changed, 5915 insertions(+), 55 deletions(-) > create mode 100644 Documentation/sound/soc/usb.rst > create mode 100644 drivers/usb/host/xhci-sec-intr.c > create mode 100644 include/linux/usb/xhci-sec-intr.h > create mode 100644 include/sound/q6usboffload.h > create mode 100644 include/sound/soc-usb.h > create mode 100644 sound/soc/qcom/qdsp6/q6usb.c > create mode 100644 sound/soc/qcom/usb_offload_utils.c > create mode 100644 sound/soc/qcom/usb_offload_utils.h > create mode 100644 sound/soc/soc-usb.c > create mode 100644 sound/usb/mixer_usb_offload.c > create mode 100644 sound/usb/mixer_usb_offload.h > create mode 100644 sound/usb/qcom/Makefile > create mode 100644 sound/usb/qcom/qc_audio_offload.c > create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.c > create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.h >
On Fri, Nov 15, 2024 at 02:42:47PM -0800, Wesley Cheng wrote: > Hi, > > On 11/6/2024 11:33 AM, Wesley Cheng wrote: > > Requesting to see if we can get some Acked-By tags, and merge on usb-next. > > Are there any more clarifications that I can help with to get this > series going? I know its been a long time coming, so folks may have > lost context, but if there are any points that might be blocking the > series from getting merged, please let me know. I would like others to review this (xhci maintainer for one), to give their blessing before I even consider this. thanks, greg k-h
On 11/15/2024 11:42 PM, Greg KH wrote: > On Fri, Nov 15, 2024 at 02:42:47PM -0800, Wesley Cheng wrote: >> Hi, >> >> On 11/6/2024 11:33 AM, Wesley Cheng wrote: >>> Requesting to see if we can get some Acked-By tags, and merge on usb-next. >> Are there any more clarifications that I can help with to get this >> series going? I know its been a long time coming, so folks may have >> lost context, but if there are any points that might be blocking the >> series from getting merged, please let me know. > I would like others to review this (xhci maintainer for one), to give > their blessing before I even consider this. Thanks, Greg...Yes, I was hoping to see if I could clarify any points for Mathias and Takashi if they had any concerns. Just so folks are also aware, we did deploy a portion of the series (specifically the XHCI sec interrupter and USB SND core changes) into devices on the market, if that adds any confidence into those changes. For the most part, there were no major issues within those drivers, and the single minor bug (in the XHCI sec intr) that we did catch was fixed in previous submissions, and should be highlighted in the change revision list. Thanks Wesley Cheng
On Tue, 19 Nov 2024 18:50:52 +0100, Wesley Cheng wrote: > > > On 11/15/2024 11:42 PM, Greg KH wrote: > > On Fri, Nov 15, 2024 at 02:42:47PM -0800, Wesley Cheng wrote: > >> Hi, > >> > >> On 11/6/2024 11:33 AM, Wesley Cheng wrote: > >>> Requesting to see if we can get some Acked-By tags, and merge on usb-next. > >> Are there any more clarifications that I can help with to get this > >> series going? I know its been a long time coming, so folks may have > >> lost context, but if there are any points that might be blocking the > >> series from getting merged, please let me know. > > I would like others to review this (xhci maintainer for one), to give > > their blessing before I even consider this. > > Thanks, Greg...Yes, I was hoping to see if I could clarify any points for Mathias and Takashi if they had any concerns. Just so folks are also aware, we did deploy a portion of the series (specifically the XHCI sec interrupter and USB SND core changes) into devices on the market, if that adds any confidence into those changes. For the most part, there were no major issues within those drivers, and the single minor bug (in the XHCI sec intr) that we did catch was fixed in previous submissions, and should be highlighted in the change revision list. Well, from the sound subsystem side, the only concerns are the design issues: namely, whether the implementations with two cards are acceptable, and whether the current control of PCM mapping is OK from the user POV. IIRC, there were discussions with Intel people and others, and I haven't followed whether we got consensus. If we reached some agreement, it'd be appreciated if you can put acks from them in the patches, too. The internal implementation details can be adjusted later, but those two must be set in stone after merging the stuff to the upstream. (BTW, the mail address of Pierre changed; I corrected in this mail.) thanks, Takashi
On 11/20/2024 4:39 AM, Takashi Iwai wrote: > On Tue, 19 Nov 2024 18:50:52 +0100, > Wesley Cheng wrote: >> >> On 11/15/2024 11:42 PM, Greg KH wrote: >>> On Fri, Nov 15, 2024 at 02:42:47PM -0800, Wesley Cheng wrote: >>>> Hi, >>>> >>>> On 11/6/2024 11:33 AM, Wesley Cheng wrote: >>>>> Requesting to see if we can get some Acked-By tags, and merge on usb-next. >>>> Are there any more clarifications that I can help with to get this >>>> series going? I know its been a long time coming, so folks may have >>>> lost context, but if there are any points that might be blocking the >>>> series from getting merged, please let me know. >>> I would like others to review this (xhci maintainer for one), to give >>> their blessing before I even consider this. >> Thanks, Greg...Yes, I was hoping to see if I could clarify any points for Mathias and Takashi if they had any concerns. Just so folks are also aware, we did deploy a portion of the series (specifically the XHCI sec interrupter and USB SND core changes) into devices on the market, if that adds any confidence into those changes. For the most part, there were no major issues within those drivers, and the single minor bug (in the XHCI sec intr) that we did catch was fixed in previous submissions, and should be highlighted in the change revision list. > Well, from the sound subsystem side, the only concerns are the design > issues: namely, whether the implementations with two cards are > acceptable, and whether the current control of PCM mapping is OK from > the user POV. IIRC, there were discussions with Intel people and > others, and I haven't followed whether we got consensus. > If we reached some agreement, it'd be appreciated if you can put acks > from them in the patches, too. I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: 1. Exposing some of the ASoC PCM (soc-pcm) APIs to be able to be called by soc-usb (to mimic a FE open from ASoC), so we can trigger ASoC DAI ops when USB SND FE is opened. 2. Proper fallback mechanism in case offload path enablement fails to the legacy USB SND path. 3. Master kcontrol to disable offload logic for each USB SND device. IMO, both the points you mentioned correspond to the same topic. If we go with having offload being operated on one FE, then there is no need for the kcontrol of PCM mapping. If we have two cards, then we will need the control for offload device mapping. Can't speak for Pierre, but at least with my discussions with him, I don't think he's against the two card design, just as long as we have the proper kcontrol that notifies userspace of how to utilize the offload path. > The internal implementation details can be adjusted later, but those > two must be set in stone after merging the stuff to the upstream. > > (BTW, the mail address of Pierre changed; I corrected in this mail.) > Thanks for updating the email address. Thanks Wesley Cheng
Sorry to chime in late, I only look at email occasionally. >> Well, from the sound subsystem side, the only concerns are the design >> issues: namely, whether the implementations with two cards are >> acceptable, and whether the current control of PCM mapping is OK from >> the user POV. IIRC, there were discussions with Intel people and >> others, and I haven't followed whether we got consensus. >> If we reached some agreement, it'd be appreciated if you can put acks >> from them in the patches, too. My Reviewed-by tags were added in the last updates. I am not sure if anyone else at Intel had the time to review this large patchset. > I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. Having a single USB card in IMHO more complicated: what happens for example if you plug-in two or more USB devices? Which of the USB cards will expose an optimized path? The design with an ASoC-based card which exposes as many PCM devices as the SOC can support is simpler conceptually and scales well. This would allow e.g. to allocate these PCM devices with different policies (last plugged, preferred, etc). Conceptually for the simple case with a single USB device, it does not really matter if there are two cards or not. What matters is that there is a clear mapping visible to userspace so that application can decide to use the optimized PCM device, when enabled, instead of the legacy one. And in the end, the application is *always* in control in terms of routing. It’s really similar to the compress offload path, some application changes will be required. > > 1. Exposing some of the ASoC PCM (soc-pcm) APIs to be able to be called by soc-usb (to mimic a FE open from ASoC), so we can trigger ASoC DAI ops when USB SND FE is opened. > > 2. Proper fallback mechanism in case offload path enablement fails to the legacy USB SND path. > > 3. Master kcontrol to disable offload logic for each USB SND device. > > IMO, both the points you mentioned correspond to the same topic. If we go with having offload being operated on one FE, then there is no need for the kcontrol of PCM mapping. If we have two cards, then we will need the control for offload device mapping. Can't speak for Pierre, but at least with my discussions with him, I don't think he's against the two card design, just as long as we have the proper kcontrol that notifies userspace of how to utilize the offload path. Even if there’s a single card you need to have a mapping between a ‘legacy’ PCM device and an ‘optimized’ one. This would be a scalar mapping instead of a (card, device) pair, but it’s a minor change. -Pierre
On 2024-11-15 11:42 PM, Wesley Cheng wrote: > Hi, > > On 11/6/2024 11:33 AM, Wesley Cheng wrote: >> Requesting to see if we can get some Acked-By tags, and merge on usb-next. > Hi Cheng, I'd consider reordering the series and splitting it up so it's easier to review, 30 patches is a lot. Right now, the QCOM parts are mixed with the framework changes. While obviously we want to see user/usage of the new additions, it is probably better to see QCOM-specifics last so that we can concentrate on what impacts all of us - the framework changes. I believe that without much work one could simplify the set so that the output of: git log --oneline -n 30 looks like below. At least that's what I've done on my machine. Notice that the top 7 patches target QCOM directly and make easy candidates for being removed from the current series and put into a standalone one instead AKA a follow up. Feel free to correct me if I'm wrong in any of these. ASoC: qcom: qdsp6: Fetch USB offload mapped card and PCM device ASoC: qcom: qdsp6: Add headphone jack for offload connection status ASoC: qcom: qdsp6: Add USB backend ASoC driver for Q6 ASoC: qcom: qdsp6: q6afe: Increase APR timeout ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp ASoC: dt-bindings: Update example for enabling USB offload on SM8250 ASoC: dt-bindings: qcom,q6dsp-lpass-ports: Add USB_RX port ASoC: usb: Rediscover USB SND devices on USB port add ALSA: usb-audio: Allow for rediscovery of connected USB SND devices ALSA: usb-audio: Add USB offload route kcontrol ALSA: usb-audio: qcom: Don't allow USB offload path if PCM device is in use ALSA: usb-audio: qcom: Introduce QC USB SND offloading support ALSA: usb-audio: qcom: Add USB QMI definitions ALSA: usb-audio: Introduce USB SND platform op callbacks ASoC: doc: Add documentation for SOC USB ASoC: usb: Fetch ASoC card and pcm device information ASoC: usb: Create SOC USB SND jack kcontrol ASoC: usb: Add PCM format check API for USB backend ASoC: Add SOC USB APIs for adding an USB backend ALSA: usb-audio: Prevent starting of audio stream if in use ALSA: usb-audio: Save UAC sample size information ALSA: usb-audio: Check for support for requested audio format ALSA: usb-audio: Export USB SND APIs for modules ALSA: Add USB audio device jack type usb: dwc3: Specify maximum number of XHCI interrupters usb: host: xhci-plat: Set XHCI max interrupters if property is present usb: host: xhci-mem: Allow for interrupter clients to choose specific index usb: host: xhci-mem: Cleanup pending secondary event ring events xhci: sec-intr: add initial api to register a secondary interrupter entity usb: host: xhci: Repurpose event handler for skipping interrupter events >> >> Mathias Nyman (1): >> xhci: sec-intr: add initial api to register a secondary interrupter >> entity >> >> Wesley Cheng (29): >> usb: host: xhci: Repurpose event handler for skipping interrupter >> events >> usb: host: xhci-mem: Cleanup pending secondary event ring events >> usb: host: xhci-mem: Allow for interrupter clients to choose specific >> index >> usb: host: xhci-plat: Set XHCI max interrupters if property is present >> usb: dwc3: Specify maximum number of XHCI interrupters >> ALSA: Add USB audio device jack type >> ALSA: usb-audio: Export USB SND APIs for modules >> ALSA: usb-audio: Check for support for requested audio format >> ALSA: usb-audio: Save UAC sample size information >> ALSA: usb-audio: Prevent starting of audio stream if in use >> ASoC: Add SOC USB APIs for adding an USB backend >> ASoC: usb: Add PCM format check API for USB backend >> ASoC: usb: Create SOC USB SND jack kcontrol >> ASoC: usb: Fetch ASoC card and pcm device information >> ASoC: doc: Add documentation for SOC USB >> ASoC: dt-bindings: qcom,q6dsp-lpass-ports: Add USB_RX port >> ASoC: dt-bindings: Update example for enabling USB offload on SM8250 >> ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp >> ASoC: qcom: qdsp6: q6afe: Increase APR timeout >> ASoC: qcom: qdsp6: Add USB backend ASoC driver for Q6 >> ASoC: qcom: qdsp6: Add headphone jack for offload connection status >> ASoC: qcom: qdsp6: Fetch USB offload mapped card and PCM device >> ALSA: usb-audio: Introduce USB SND platform op callbacks >> ALSA: usb-audio: qcom: Add USB QMI definitions >> ALSA: usb-audio: qcom: Introduce QC USB SND offloading support >> ALSA: usb-audio: qcom: Don't allow USB offload path if PCM device is >> in use >> ALSA: usb-audio: Add USB offload route kcontrol >> ALSA: usb-audio: Allow for rediscovery of connected USB SND devices >> ASoC: usb: Rediscover USB SND devices on USB port add >> >> .../bindings/sound/qcom,sm8250.yaml | 15 + >> Documentation/sound/soc/index.rst | 1 + >> Documentation/sound/soc/usb.rst | 491 ++++ >> drivers/usb/dwc3/core.c | 12 + >> drivers/usb/dwc3/core.h | 2 + >> drivers/usb/dwc3/host.c | 3 + >> drivers/usb/host/Kconfig | 11 + >> drivers/usb/host/Makefile | 2 + >> drivers/usb/host/xhci-mem.c | 31 +- >> drivers/usb/host/xhci-plat.c | 2 + >> drivers/usb/host/xhci-ring.c | 54 +- >> drivers/usb/host/xhci-sec-intr.c | 439 ++++ >> drivers/usb/host/xhci.c | 2 +- >> drivers/usb/host/xhci.h | 14 +- >> .../sound/qcom,q6dsp-lpass-ports.h | 1 + >> include/linux/mod_devicetable.h | 2 +- >> include/linux/usb/xhci-sec-intr.h | 70 + >> include/sound/jack.h | 4 +- >> include/sound/q6usboffload.h | 20 + >> include/sound/soc-usb.h | 147 ++ >> include/uapi/linux/input-event-codes.h | 3 +- >> sound/core/jack.c | 6 +- >> sound/soc/Kconfig | 10 + >> sound/soc/Makefile | 2 + >> sound/soc/qcom/Kconfig | 15 + >> sound/soc/qcom/Makefile | 2 + >> sound/soc/qcom/qdsp6/Makefile | 1 + >> sound/soc/qcom/qdsp6/q6afe-dai.c | 60 + >> sound/soc/qcom/qdsp6/q6afe.c | 194 +- >> sound/soc/qcom/qdsp6/q6afe.h | 36 +- >> sound/soc/qcom/qdsp6/q6dsp-lpass-ports.c | 23 + >> sound/soc/qcom/qdsp6/q6dsp-lpass-ports.h | 1 + >> sound/soc/qcom/qdsp6/q6routing.c | 32 +- >> sound/soc/qcom/qdsp6/q6usb.c | 391 ++++ >> sound/soc/qcom/sm8250.c | 24 +- >> sound/soc/qcom/usb_offload_utils.c | 56 + >> sound/soc/qcom/usb_offload_utils.h | 30 + >> sound/soc/soc-usb.c | 369 +++ >> sound/usb/Kconfig | 25 + >> sound/usb/Makefile | 4 +- >> sound/usb/card.c | 106 + >> sound/usb/card.h | 17 + >> sound/usb/endpoint.c | 1 + >> sound/usb/format.c | 1 + >> sound/usb/helper.c | 1 + >> sound/usb/mixer_usb_offload.c | 102 + >> sound/usb/mixer_usb_offload.h | 17 + >> sound/usb/pcm.c | 104 +- >> sound/usb/pcm.h | 11 + >> sound/usb/qcom/Makefile | 2 + >> sound/usb/qcom/qc_audio_offload.c | 1974 +++++++++++++++++ >> sound/usb/qcom/usb_audio_qmi_v01.c | 863 +++++++ >> sound/usb/qcom/usb_audio_qmi_v01.h | 164 ++ >> 53 files changed, 5915 insertions(+), 55 deletions(-) >> create mode 100644 Documentation/sound/soc/usb.rst >> create mode 100644 drivers/usb/host/xhci-sec-intr.c >> create mode 100644 include/linux/usb/xhci-sec-intr.h >> create mode 100644 include/sound/q6usboffload.h >> create mode 100644 include/sound/soc-usb.h >> create mode 100644 sound/soc/qcom/qdsp6/q6usb.c >> create mode 100644 sound/soc/qcom/usb_offload_utils.c >> create mode 100644 sound/soc/qcom/usb_offload_utils.h >> create mode 100644 sound/soc/soc-usb.c >> create mode 100644 sound/usb/mixer_usb_offload.c >> create mode 100644 sound/usb/mixer_usb_offload.h >> create mode 100644 sound/usb/qcom/Makefile >> create mode 100644 sound/usb/qcom/qc_audio_offload.c >> create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.c >> create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.h >> >
On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: > Sorry to chime in late, I only look at email occasionally. > ... > My Reviewed-by tags were added in the last updates. I am not sure if anyone else at Intel had the time to review this large patchset. > >> I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: > > The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. Well, I believe a lot has changed since then, not sure if USB Audio Offload (UAOL) was even stable on the Windows solution back then. Obviously we want to incorporate what we have learned during all that time into our solution before it lands on upstream. UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. Currently struct snd_soc_usb does not represent any component at all. Lack of codec representative, component representative and, given my current understanding, mixed dependency of sound/usb on sound/soc/soc-usb does lead to hard-to-understand ASoC solution. > > Having a single USB card in IMHO more complicated: what happens for example if you plug-in two or more USB devices? Which of the USB cards will expose an optimized path? The design with an ASoC-based card which exposes as many PCM devices as the SOC can support is simpler conceptually and scales well. This would allow e.g. to allocate these PCM devices with different policies (last plugged, preferred, etc). > > Conceptually for the simple case with a single USB device, it does not really matter if there are two cards or not. What matters is that there is a clear mapping visible to userspace so that application can decide to use the optimized PCM device, when enabled, instead of the legacy one. And in the end, the application is *always* in control in terms of routing. It’s really similar to the compress offload path, some application changes will be required. > >> >> 1. Exposing some of the ASoC PCM (soc-pcm) APIs to be able to be called by soc-usb (to mimic a FE open from ASoC), so we can trigger ASoC DAI ops when USB SND FE is opened. >> >> 2. Proper fallback mechanism in case offload path enablement fails to the legacy USB SND path. >> >> 3. Master kcontrol to disable offload logic for each USB SND device. >> >> IMO, both the points you mentioned correspond to the same topic. If we go with having offload being operated on one FE, then there is no need for the kcontrol of PCM mapping. If we have two cards, then we will need the control for offload device mapping. Can't speak for Pierre, but at least with my discussions with him, I don't think he's against the two card design, just as long as we have the proper kcontrol that notifies userspace of how to utilize the offload path. > > Even if there’s a single card you need to have a mapping between a ‘legacy’ PCM device and an ‘optimized’ one. This would be a scalar mapping instead of a (card, device) pair, but it’s a minor change. > > -Pierre
On Tue, Dec 03, 2024 at 05:17:48PM +0100, Cezary Rojewski wrote: > On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: > > Sorry to chime in late, I only look at email occasionally. > > > > ... > > > My Reviewed-by tags were added in the last updates. I am not sure if anyone else at Intel had the time to review this large patchset. > > > > > I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: > > > > The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. > > > Well, I believe a lot has changed since then, not sure if USB Audio Offload > (UAOL) was even stable on the Windows solution back then. Obviously we want > to incorporate what we have learned during all that time into our solution > before it lands on upstream. Great, can you help review this series please? thanks, greg k-h
Hi Cezary, On 12/3/2024 8:17 AM, Cezary Rojewski wrote: > On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: >> Sorry to chime in late, I only look at email occasionally. >> > > ... > >> My Reviewed-by tags were added in the last updates. I am not sure if anyone else at Intel had the time to review this large patchset. >> >>> I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: >> >> The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. > > > Well, I believe a lot has changed since then, not sure if USB Audio Offload (UAOL) was even stable on the Windows solution back then. Obviously we want to incorporate what we have learned during all that time into our solution before it lands on upstream. > Hard to comment further without more details on the lessons learnt you had on Windows. I just want to make sure we're talking about the same feature here, because I see sprinkles of the xHCI audio sideband (section 7.9) on the Windows documentation without much details on how its implemented, which is different than what is presented here. > UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. > Just to clarify, "struct snd_soc_usb" does have some correlation with our "codec" entity within the QCOM ASoC design. This would be the q6usb driver. > Currently struct snd_soc_usb does not represent any component at all. Lack of codec representative, component representative and, given my current understanding, mixed dependency of sound/usb on sound/soc/soc-usb does lead to hard-to-understand ASoC solution. IMO the dependency on USB SND is necessary, so that we can leverage all the pre-existing sequences used to identify USB audio devices, and have some ability to utilize USB HCD APIs as well within the offload driver. > >> >> Having a single USB card in IMHO more complicated: what happens for example if you plug-in two or more USB devices? Which of the USB cards will expose an optimized path? The design with an ASoC-based card which exposes as many PCM devices as the SOC can support is simpler conceptually and scales well. This would allow e.g. to allocate these PCM devices with different policies (last plugged, preferred, etc). >> >> Conceptually for the simple case with a single USB device, it does not really matter if there are two cards or not. What matters is that there is a clear mapping visible to userspace so that application can decide to use the optimized PCM device, when enabled, instead of the legacy one. And in the end, the application is *always* in control in terms of routing. It’s really similar to the compress offload path, some application changes will be required. >> >>> >>> 1. Exposing some of the ASoC PCM (soc-pcm) APIs to be able to be called by soc-usb (to mimic a FE open from ASoC), so we can trigger ASoC DAI ops when USB SND FE is opened. >>> >>> 2. Proper fallback mechanism in case offload path enablement fails to the legacy USB SND path. >>> >>> 3. Master kcontrol to disable offload logic for each USB SND device. >>> >>> IMO, both the points you mentioned correspond to the same topic. If we go with having offload being operated on one FE, then there is no need for the kcontrol of PCM mapping. If we have two cards, then we will need the control for offload device mapping. Can't speak for Pierre, but at least with my discussions with him, I don't think he's against the two card design, just as long as we have the proper kcontrol that notifies userspace of how to utilize the offload path. >> >> Even if there’s a single card you need to have a mapping between a ‘legacy’ PCM device and an ‘optimized’ one. This would be a scalar mapping instead of a (card, device) pair, but it’s a minor change. >> >> -Pierre >
On 2024-12-03 5:57 PM, Greg KH wrote: > On Tue, Dec 03, 2024 at 05:17:48PM +0100, Cezary Rojewski wrote: >> On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: >>> Sorry to chime in late, I only look at email occasionally. ... >>>> I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: >>> >>> The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. >> >> >> Well, I believe a lot has changed since then, not sure if USB Audio Offload >> (UAOL) was even stable on the Windows solution back then. Obviously we want >> to incorporate what we have learned during all that time into our solution >> before it lands on upstream. > > Great, can you help review this series please? Hi Greg, This series is large and I'd suggest to split it up, what I touched on in my recent reply [1]. Please correct me if I'm wrong, but you mostly care about drivers/usb/* part. If so, the existing set could be split into USB-changes series, ALSA/ASoC-framework series and a third, holding bulk of QCOM-specific patches. Me and my team care mostly about the sound/* part and we don't hold much expertise in USB. I believe Mathias covers this part well though. [1]: https://lore.kernel.org/linux-sound/a8ece816-3d4c-4d60-b7c1-a7f7919325f3@intel.com/ Czarek
On 2024-12-03 9:38 PM, Wesley Cheng wrote: > Hi Cezary, > > On 12/3/2024 8:17 AM, Cezary Rojewski wrote: >> On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: >>> Sorry to chime in late, I only look at email occasionally. ... >>> The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. >> >> >> Well, I believe a lot has changed since then, not sure if USB Audio Offload (UAOL) was even stable on the Windows solution back then. Obviously we want to incorporate what we have learned during all that time into our solution before it lands on upstream. >> > > Hard to comment further without more details on the lessons learnt you had on Windows. I just want to make sure we're talking about the same feature here, because I see sprinkles of the xHCI audio sideband (section 7.9) on the Windows documentation without much details on how its implemented, which is different than what is presented here. The comment was directed towards mention of Intel, 2018 and Rakesh. The decisions made then do not bind us, and current Intel's Audio team has a clean slide. Wanted to make sure it's clear. >> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >> > > Just to clarify, "struct snd_soc_usb" does have some correlation with our "codec" entity within the QCOM ASoC design. This would be the q6usb driver. > > >> Currently struct snd_soc_usb does not represent any component at all. Lack of codec representative, component representative and, given my current understanding, mixed dependency of sound/usb on sound/soc/soc-usb does lead to hard-to-understand ASoC solution. > > > IMO the dependency on USB SND is necessary, so that we can leverage all the pre-existing sequences used to identify USB audio devices, and have some ability to utilize USB HCD APIs as well within the offload driver. So, while I do not have patches in shape good enough to be shared, what we have in mind is closer to existing HDAudio solution and how it is covered in both ALSA and ASoC. A ASoC sound card is effectively a combination of instances of struct snd_soc_component. Think of it as an MFD device. Typically at least two components are needed: - platform component, e.g.: for representing DSP-capable device - codec component, e.g.: for representing the codec device USB could be represented by such a component, listed as a dependency of a sound card. By component I literally mean it extending the base struct: stuct snd_soc_usb { struct snd_soc_component base; (...) }; In my opinion HDAudio is a good example of how to mesh existing ALSA-based implementation with ASoC. Full, well implemented behaviour of HDAudio codec device drivers is present at sound/pci/hda/patch_*.c and friends. That part of devoid of any ASoC members. At the same time, an ASoC wrapper is present at sound/soc/codecs/hda.c. It will represent each and every HDAudio codec device on the HDAudio bus as a ASoC-component. This follows the ASoC design and thus is easy understand for any daily ASoC user, at least in my opinion. Next, the USB Audio Offload streams are a limited resource but I do not see a reason to not treat it as a pool. Again, HDAudio comes into picture. The HDAudio streams are assigned and released with help of HDAudio library, code found in sound/hda/hdac_stream.c. In essence, as long as UAOL-capable streaming is allowed, a pcm->open() could approach a UAOL-lib (? component perhaps?) and perform ->assign(). If no resources available, fallback to the non-offloaded case. While I have not commented on the kcontrol part, the above means that our current design does go into a different direction. We'd like to avoid stream-assignment hardcoding i.e.: predefining who owns a UAOL-capable stream if possible. Kind regards, Czarek
On 2024-12-04 8:47 PM, Pierre-Louis Bossart wrote: > ... >> UAOL is one of our priorities right now and some (e.g.: me) prefer to >> not pollute their mind with another approaches until what they have in >> mind is crystalized. In short, I'd vote for a approach where USB >> device has a ASoC representative in sound/soc/codecs/ just like it is >> the case for HDAudio. Either that or at least a ASoC-component >> representative, a dependency for UAOL-capable card to enumerate. > > The main difference is that we don’t want the USB audio *control* part > to be seen in two places. The only requirement is to stream data with an > alternate optimized path, but all the volume control and whatnot is > supposed to be done using the regular usb-audio card. It would be > complete chaos for userspace if the same volume can be represented > differently. > > The comparison with HDaudio is not quite right either. In the case of > HDaudio, it’s an all-or-nothing solution. The external device is > controlled by one entity, either legacy or ASoC based. That choice is > made at driver probe time. In the case of USB, the application needs to > have the choice of using either the legacy path, or the optimized path > that goes through a DSP. I think the last thing you want given this > context is to make the USB audio device an ASoC codec. > > I find it rather interesting that this architectural feedback comes at > the v30, it’s unfair to Wesley really... > Hi Pierre, Obviously I'm late. After scanning the history of this one, indeed it's been a while since v1 has been sent. And thus I posted no NACKs. At the same time if I am to choose between: provide feedback vs provide no-feedback, I'd rather choose the former even if I'm to be ignored/overridden by a subsystem maintainer. The subsystem maintainers also hold the last word, and I have no problem with them merging the patches if they believe its existing shape is good-enough. For example, my team could follow up this implementation next year with a patchset expanding/updating the functionality. I see this as a viable option. Kind regards, Czarek
On 12/4/2024 1:14 PM, Cezary Rojewski wrote: > On 2024-12-03 5:57 PM, Greg KH wrote: >> On Tue, Dec 03, 2024 at 05:17:48PM +0100, Cezary Rojewski wrote: >>> On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: >>>> Sorry to chime in late, I only look at email occasionally. > > ... > >>>>> I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: >>>> >>>> The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. >>> >>> >>> Well, I believe a lot has changed since then, not sure if USB Audio Offload >>> (UAOL) was even stable on the Windows solution back then. Obviously we want >>> to incorporate what we have learned during all that time into our solution >>> before it lands on upstream. >> >> Great, can you help review this series please? > > Hi Greg, > > This series is large and I'd suggest to split it up, what I touched on in my recent reply [1]. Please correct me if I'm wrong, but you mostly care about drivers/usb/* part. If so, the existing set could be split into USB-changes series, ALSA/ASoC-framework series and a third, holding bulk of QCOM-specific patches. Me and my team care mostly about the sound/* part and we don't hold much expertise in USB. I believe Mathias covers this part well though. > I'm fine to split this into 3 different series if that helps with the reviews. I was always under the impression that when we upstream things, we need to have an end to end use case within the same series, so that folks get the full picture. I've gotten feedback where people were confused they couldn't find/follow the code flow, albeit those series were much much smaller. If Greg is ok with it, I can split it up and have a link reference to the other series. I was able to reorganize the list a bit to what you recommended. So the current layout is xHCI changes first, followed by the USB ALSA and ASoC changes, and lastly the QCOM/vendor specific modifications. Thanks Wesley Cheng > > [1]: https://lore.kernel.org/linux-sound/a8ece816-3d4c-4d60-b7c1-a7f7919325f3@intel.com/ > > Czarek
On Wed, Dec 04, 2024 at 05:15:02PM -0800, Wesley Cheng wrote: > > On 12/4/2024 1:14 PM, Cezary Rojewski wrote: > > On 2024-12-03 5:57 PM, Greg KH wrote: > >> On Tue, Dec 03, 2024 at 05:17:48PM +0100, Cezary Rojewski wrote: > >>> On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: > >>>> Sorry to chime in late, I only look at email occasionally. > > > > ... > > > >>>>> I believe Amadeusz was still against having the two card design, and wants the routing to automatically happen when playback happens on the sound card created by the USB SND layer. However, even with that kind of implementation, the major pieces brought in by this series should still be relevant, ie soc-usb and the vendor offload driver. The only thing that would really change is adding a path from the USB SND PCM ops to interact with the ASoC entities. Complexity-wise, this would obviously have a good amount of changes to the USB SND/ASoC core drivers. Some things I can think of that we'd need to introduce: > >>>> > >>>> The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. > >>> > >>> > >>> Well, I believe a lot has changed since then, not sure if USB Audio Offload > >>> (UAOL) was even stable on the Windows solution back then. Obviously we want > >>> to incorporate what we have learned during all that time into our solution > >>> before it lands on upstream. > >> > >> Great, can you help review this series please? > > > > Hi Greg, > > > > This series is large and I'd suggest to split it up, what I touched on in my recent reply [1]. Please correct me if I'm wrong, but you mostly care about drivers/usb/* part. If so, the existing set could be split into USB-changes series, ALSA/ASoC-framework series and a third, holding bulk of QCOM-specific patches. Me and my team care mostly about the sound/* part and we don't hold much expertise in USB. I believe Mathias covers this part well though. > > > > I'm fine to split this into 3 different series if that helps with the reviews. I was always under the impression that when we upstream things, we need to have an end to end use case within the same series, so that folks get the full picture. I've gotten feedback where people were confused they couldn't find/follow the code flow, albeit those series were much much smaller. If Greg is ok with it, I can split it up and have a link reference to the other series. Yes, a full patch series is best as adding infrastructure in a stand-alone series that no one uses isn't going to work well. > I was able to reorganize the list a bit to what you recommended. So the current layout is xHCI changes first, followed by the USB ALSA and ASoC changes, and lastly the QCOM/vendor specific modifications. That sounds reasonable, hopefully it lets others review it easier. thanks, greg k-h
On 12/4/2024 2:01 PM, Cezary Rojewski wrote: > On 2024-12-03 9:38 PM, Wesley Cheng wrote: >> Hi Cezary, >> >> On 12/3/2024 8:17 AM, Cezary Rojewski wrote: >>> On 2024-12-01 4:14 AM, Pierre-Louis Bossart wrote: >>>> Sorry to chime in late, I only look at email occasionally. > > ... > >>>> The notion of two cards was agreed inside Intel as far back as 2018, when Rakesh first looked at USB offload. >>> >>> >>> Well, I believe a lot has changed since then, not sure if USB Audio Offload (UAOL) was even stable on the Windows solution back then. Obviously we want to incorporate what we have learned during all that time into our solution before it lands on upstream. >>> >> >> Hard to comment further without more details on the lessons learnt you had on Windows. I just want to make sure we're talking about the same feature here, because I see sprinkles of the xHCI audio sideband (section 7.9) on the Windows documentation without much details on how its implemented, which is different than what is presented here. > > The comment was directed towards mention of Intel, 2018 and Rakesh. The decisions made then do not bind us, and current Intel's Audio team has a clean slide. Wanted to make sure it's clear. > >>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >>> >> >> Just to clarify, "struct snd_soc_usb" does have some correlation with our "codec" entity within the QCOM ASoC design. This would be the q6usb driver. >> >> >>> Currently struct snd_soc_usb does not represent any component at all. Lack of codec representative, component representative and, given my current understanding, mixed dependency of sound/usb on sound/soc/soc-usb does lead to hard-to-understand ASoC solution. >> >> >> IMO the dependency on USB SND is necessary, so that we can leverage all the pre-existing sequences used to identify USB audio devices, and have some ability to utilize USB HCD APIs as well within the offload driver. > > So, while I do not have patches in shape good enough to be shared, what we have in mind is closer to existing HDAudio solution and how it is covered in both ALSA and ASoC. > > A ASoC sound card is effectively a combination of instances of struct snd_soc_component. Think of it as an MFD device. Typically at least two components are needed: > > - platform component, e.g.: for representing DSP-capable device > - codec component, e.g.: for representing the codec device > > USB could be represented by such a component, listed as a dependency of a sound card. By component I literally mean it extending the base struct: > > stuct snd_soc_usb { > struct snd_soc_component base; > (...) > }; > > In my opinion HDAudio is a good example of how to mesh existing ALSA-based implementation with ASoC. Full, well implemented behaviour of HDAudio codec device drivers is present at sound/pci/hda/patch_*.c and friends. That part of devoid of any ASoC members. At the same time, an ASoC wrapper is present at sound/soc/codecs/hda.c. It will represent each and every HDAudio codec device on the HDAudio bus as a ASoC-component. This follows the ASoC design and thus is easy understand for any daily ASoC user, at least in my opinion. > > Next, the USB Audio Offload streams are a limited resource but I do not see a reason to not treat it as a pool. Again, HDAudio comes into picture. The HDAudio streams are assigned and released with help of HDAudio library, code found in sound/hda/hdac_stream.c. In essence, as long as UAOL-capable streaming is allowed, a pcm->open() could approach a UAOL-lib (? component perhaps?) and perform ->assign(). If no resources available, fallback to the non-offloaded case. > > While I have not commented on the kcontrol part, the above means that our current design does go into a different direction. We'd like to avoid stream-assignment hardcoding i.e.: predefining who owns a UAOL-capable stream if possible. > > Thanks for sharing the implementation for HDA. I did take a look to the best of my ability on how the HDAudio library was built, and I see the differences that are there with the current proposal. However, I think modifying the current design to something like that would also require the QCOM ASoC side to change a bit too. As mentioned by Pierre, I think its worthwhile to see if we can get the initial changes in, which is the major part of the challenge. For the most part, I think we could eventually refactor soc-usb to behave similarly to what hda_bind.c is doing. Both entities are the ones that handle linking (or creation in case of HDA) of ASoC components. The one major factor I can see is that within the HDA implementation vs USB SND is that, for USB, hot plugging is a common practice, and that's a scenario that will probably need more discussion if we do make that shift. Anyway, I just wanted to acknowledge the technical details that are utilized by HDAudio, and that we could potentially get there with USB SoC as well. Thanks Wesley Cheng
On 12/4/2024 2:49 PM, Pierre-Louis Bossart wrote: > >> >> >>>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >>> The main difference is that we don’t want the USB audio *control* part to be seen in two places. The only requirement is to stream data with an alternate optimized path, but all the volume control and whatnot is supposed to be done using the regular usb-audio card. It would be complete chaos for userspace if the same volume can be represented differently. >>> The comparison with HDaudio is not quite right either. In the case of HDaudio, it’s an all-or-nothing solution. The external device is controlled by one entity, either legacy or ASoC based. That choice is made at driver probe time. In the case of USB, the application needs to have the choice of using either the legacy path, or the optimized path that goes through a DSP. I think the last thing you want given this context is to make the USB audio device an ASoC codec. >>> I find it rather interesting that this architectural feedback comes at the v30, it’s unfair to Wesley really... >> >> Hi Pierre, >> >> Obviously I'm late. After scanning the history of this one, indeed it's been a while since v1 has been sent. And thus I posted no NACKs. At the same time if I am to choose between: provide feedback vs provide no-feedback, I'd rather choose the former even if I'm to be ignored/overridden by a subsystem maintainer. >> >> The subsystem maintainers also hold the last word, and I have no problem with them merging the patches if they believe its existing shape is good-enough. For example, my team could follow up this implementation next year with a patchset expanding/updating the functionality. I see this as a viable option. > > That’s what we had in mind before I left Intel. The interfaces seen by userspace are PCM devices and kcontrols, it doesn’t matter too much if there is one card, two cards, and if the implementation relies on an ASoC codec, a library or something else. > The bulk of the work is to enable the USB offload from top to bottom, by changing PipeWire/CRAS/HAL to select the new optimized path when available and deal with plug/unplug events. > Improvements at the kernel level can be done later if required. It’s hard to argue that the proposal in this series is fundamentally broken, but as usual it’s likely that some requirements are missing or not known yet. The same thing happened with compressed offload, none one thought about gapless playback until Android made it a requirement. Maybe what we’d need is a ‘protocol version’ for USB offload so that changes can be tracked and handled? Thanks for chiming in, Pierre. So for now, with the next revision I have prepared, I'm currently adding: 1. Some improvements to xHCI sideband to account for core sequences that need to be notified to the offload driver, ie transfer ring free 2. Moved the USB SND offload mixer driver into the QC vendor module for now, as instructed by Takashi: https://lore.kernel.org/linux-usb/87cyiiaxpc.wl-tiwai@suse.de/ 3. Added separate kcontrols for fetching mapped PCM device and card indexes (versus one that returns a card and PCM device pair [array]) 4. Removed some jack controls (enable/disable) from soc-usb 5. Updated documentation for #3 Those are the major changes that will come in the next revision. I'm just trying to figure out who/where the "protocol version" should be checked if we decided to add it. (or if we need to check for it anywhere...) From the userspace perspective, it should be agnostic to how we've implemented offloading from the kernel, and I don't see any major shifts in how userspace implements things even if we make improvements from kernel. Thanks Wesley Cheng
On 12/5/2024 4:53 PM, Wesley Cheng wrote: > On 12/4/2024 2:49 PM, Pierre-Louis Bossart wrote: >>> >>>>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >>>> The main difference is that we don’t want the USB audio *control* part to be seen in two places. The only requirement is to stream data with an alternate optimized path, but all the volume control and whatnot is supposed to be done using the regular usb-audio card. It would be complete chaos for userspace if the same volume can be represented differently. >>>> The comparison with HDaudio is not quite right either. In the case of HDaudio, it’s an all-or-nothing solution. The external device is controlled by one entity, either legacy or ASoC based. That choice is made at driver probe time. In the case of USB, the application needs to have the choice of using either the legacy path, or the optimized path that goes through a DSP. I think the last thing you want given this context is to make the USB audio device an ASoC codec. >>>> I find it rather interesting that this architectural feedback comes at the v30, it’s unfair to Wesley really... >>> Hi Pierre, >>> >>> Obviously I'm late. After scanning the history of this one, indeed it's been a while since v1 has been sent. And thus I posted no NACKs. At the same time if I am to choose between: provide feedback vs provide no-feedback, I'd rather choose the former even if I'm to be ignored/overridden by a subsystem maintainer. >>> >>> The subsystem maintainers also hold the last word, and I have no problem with them merging the patches if they believe its existing shape is good-enough. For example, my team could follow up this implementation next year with a patchset expanding/updating the functionality. I see this as a viable option. >> That’s what we had in mind before I left Intel. The interfaces seen by userspace are PCM devices and kcontrols, it doesn’t matter too much if there is one card, two cards, and if the implementation relies on an ASoC codec, a library or something else. >> The bulk of the work is to enable the USB offload from top to bottom, by changing PipeWire/CRAS/HAL to select the new optimized path when available and deal with plug/unplug events. >> Improvements at the kernel level can be done later if required. It’s hard to argue that the proposal in this series is fundamentally broken, but as usual it’s likely that some requirements are missing or not known yet. The same thing happened with compressed offload, none one thought about gapless playback until Android made it a requirement. Maybe what we’d need is a ‘protocol version’ for USB offload so that changes can be tracked and handled? > > Thanks for chiming in, Pierre. So for now, with the next revision I have prepared, I'm currently adding: > > 1. Some improvements to xHCI sideband to account for core sequences that need to be notified to the offload driver, ie transfer ring free > > 2. Moved the USB SND offload mixer driver into the QC vendor module for now, as instructed by Takashi: > > https://lore.kernel.org/linux-usb/87cyiiaxpc.wl-tiwai@suse.de/ > > 3. Added separate kcontrols for fetching mapped PCM device and card indexes (versus one that returns a card and PCM device pair [array]) > > 4. Removed some jack controls (enable/disable) from soc-usb > > 5. Updated documentation for #3 > > > Those are the major changes that will come in the next revision. I'm just trying to figure out who/where the "protocol version" should be checked if we decided to add it. (or if we need to check for it anywhere...) From the userspace perspective, it should be agnostic to how we've implemented offloading from the kernel, and I don't see any major shifts in how userspace implements things even if we make improvements from kernel. Hi Takashi, Could you possibly help share some direction on what you think of the current design, and if you think its detrimental that we make modifications mentioned by Cezary? I have the next revision ready for review, but I wanted to get a better sense on the likeliness of this landing upstream w/o the major modifications. Thanks Wesley Cheng > > Thanks > > Wesley Cheng >
On 2024-12-06 1:28 AM, Wesley Cheng wrote: > > On 12/4/2024 2:01 PM, Cezary Rojewski wrote: >> On 2024-12-03 9:38 PM, Wesley Cheng wrote: >>> Hi Cezary, >>> >>> On 12/3/2024 8:17 AM, Cezary Rojewski wrote: ... >>>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >>>> >>> >>> Just to clarify, "struct snd_soc_usb" does have some correlation with our "codec" entity within the QCOM ASoC design. This would be the q6usb driver. >>> >>> >>>> Currently struct snd_soc_usb does not represent any component at all. Lack of codec representative, component representative and, given my current understanding, mixed dependency of sound/usb on sound/soc/soc-usb does lead to hard-to-understand ASoC solution. >>> >>> >>> IMO the dependency on USB SND is necessary, so that we can leverage all the pre-existing sequences used to identify USB audio devices, and have some ability to utilize USB HCD APIs as well within the offload driver. >> >> So, while I do not have patches in shape good enough to be shared, what we have in mind is closer to existing HDAudio solution and how it is covered in both ALSA and ASoC. >> >> A ASoC sound card is effectively a combination of instances of struct snd_soc_component. Think of it as an MFD device. Typically at least two components are needed: >> >> - platform component, e.g.: for representing DSP-capable device >> - codec component, e.g.: for representing the codec device >> >> USB could be represented by such a component, listed as a dependency of a sound card. By component I literally mean it extending the base struct: >> >> stuct snd_soc_usb { >> struct snd_soc_component base; >> (...) >> }; >> >> In my opinion HDAudio is a good example of how to mesh existing ALSA-based implementation with ASoC. Full, well implemented behaviour of HDAudio codec device drivers is present at sound/pci/hda/patch_*.c and friends. That part of devoid of any ASoC members. At the same time, an ASoC wrapper is present at sound/soc/codecs/hda.c. It will represent each and every HDAudio codec device on the HDAudio bus as a ASoC-component. This follows the ASoC design and thus is easy understand for any daily ASoC user, at least in my opinion. >> >> Next, the USB Audio Offload streams are a limited resource but I do not see a reason to not treat it as a pool. Again, HDAudio comes into picture. The HDAudio streams are assigned and released with help of HDAudio library, code found in sound/hda/hdac_stream.c. In essence, as long as UAOL-capable streaming is allowed, a pcm->open() could approach a UAOL-lib (? component perhaps?) and perform ->assign(). If no resources available, fallback to the non-offloaded case. >> >> While I have not commented on the kcontrol part, the above means that our current design does go into a different direction. We'd like to avoid stream-assignment hardcoding i.e.: predefining who owns a UAOL-capable stream if possible. >> >> > > Thanks for sharing the implementation for HDA. I did take a look to the best of my ability on how the HDAudio library was built, and I see the differences that are there with the current proposal. However, I think modifying the current design to something like that would also require the QCOM ASoC side to change a bit too. As mentioned by Pierre, I think its worthwhile to see if we can get the initial changes in, which is the major part of the challenge. For the most part, I think we could eventually refactor soc-usb to behave similarly to what hda_bind.c is doing. Both entities are the ones that handle linking (or creation in case of HDA) of ASoC components. The one major factor I can see is that within the HDA implementation vs USB SND is that, for USB, hot plugging is a common practice, and that's a scenario that will probably need more discussion if we do make that shift. > > > Anyway, I just wanted to acknowledge the technical details that are utilized by HDAudio, and that we could potentially get there with USB SoC as well. Hello, After analyzing the USB for some time to get an even better understanding of what's present in this series, I arrived at a conclusion that indeed, the approach present here clearly differs from what I would call _by the book_ approach for hardware-based USB Audio offloading. All sections below refer to the public xHCI spec [1]. A high-level bullets for the probing procedure: 1. xHCI root and resources probe() as they do today 2. xHCI reads HCCPARAMS2 (section 5.3.9) and checks GSC bit 2a. If GSC==0, the UAOL enumeration halts 3. xHCI sends GET_EXTPROP_TRB with ECI=1 to retrieve capabilities supported (section 4.6.17 and Table 4-3) 3a. If AUDIO_SIDEBAND bit is not set, the UAOL enumeration halts 4. Create a platform_device instance. This instance will act as a bridge between USB and ASoC world. For simplicity, let's call it usb-component, a representative of USB in struct snd_soc_component. 5. On the platform_device->probe() the device requests information about resources available from xHCI (section 7.9.1.1), ECI=1, SubType=001 6. Allocate a list of streams per device or list per endpoint supported based on the data retrieved with the followup TRB of SubType=010. (things get more complicated here, stopping) Now, any time a sound card with bound usb-component would begin PCM operation, starting with substream->open(), the component would first check if the device and/or the endpoint has resources necessary to support offloading. If not, it would fallback to the non-offloaded case. I do not see implementation for any TRBs I mentioned above here. The HCCPARAMS2 seem to be ignored too. At the same time, I'm unsure about the "interrupters" piece. I believe they make the approach present here somehow work, yet may not be required by the _by the book_ approach at all. [1]: https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/extensible-host-controler-interface-usb-xhci.pdf Kind regards, Czarek
On Tue, 10 Dec 2024 01:59:10 +0100, Wesley Cheng wrote: > > On 12/5/2024 4:53 PM, Wesley Cheng wrote: > > On 12/4/2024 2:49 PM, Pierre-Louis Bossart wrote: > >>> > >>>>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. > >>>> The main difference is that we don’t want the USB audio *control* part to be seen in two places. The only requirement is to stream data with an alternate optimized path, but all the volume control and whatnot is supposed to be done using the regular usb-audio card. It would be complete chaos for userspace if the same volume can be represented differently. > >>>> The comparison with HDaudio is not quite right either. In the case of HDaudio, it’s an all-or-nothing solution. The external device is controlled by one entity, either legacy or ASoC based. That choice is made at driver probe time. In the case of USB, the application needs to have the choice of using either the legacy path, or the optimized path that goes through a DSP. I think the last thing you want given this context is to make the USB audio device an ASoC codec. > >>>> I find it rather interesting that this architectural feedback comes at the v30, it’s unfair to Wesley really... > >>> Hi Pierre, > >>> > >>> Obviously I'm late. After scanning the history of this one, indeed it's been a while since v1 has been sent. And thus I posted no NACKs. At the same time if I am to choose between: provide feedback vs provide no-feedback, I'd rather choose the former even if I'm to be ignored/overridden by a subsystem maintainer. > >>> > >>> The subsystem maintainers also hold the last word, and I have no problem with them merging the patches if they believe its existing shape is good-enough. For example, my team could follow up this implementation next year with a patchset expanding/updating the functionality. I see this as a viable option. > >> That’s what we had in mind before I left Intel. The interfaces seen by userspace are PCM devices and kcontrols, it doesn’t matter too much if there is one card, two cards, and if the implementation relies on an ASoC codec, a library or something else. > >> The bulk of the work is to enable the USB offload from top to bottom, by changing PipeWire/CRAS/HAL to select the new optimized path when available and deal with plug/unplug events. > >> Improvements at the kernel level can be done later if required. It’s hard to argue that the proposal in this series is fundamentally broken, but as usual it’s likely that some requirements are missing or not known yet. The same thing happened with compressed offload, none one thought about gapless playback until Android made it a requirement. Maybe what we’d need is a ‘protocol version’ for USB offload so that changes can be tracked and handled? > > > > Thanks for chiming in, Pierre. So for now, with the next revision I have prepared, I'm currently adding: > > > > 1. Some improvements to xHCI sideband to account for core sequences that need to be notified to the offload driver, ie transfer ring free > > > > 2. Moved the USB SND offload mixer driver into the QC vendor module for now, as instructed by Takashi: > > > > https://lore.kernel.org/linux-usb/87cyiiaxpc.wl-tiwai@suse.de/ > > > > 3. Added separate kcontrols for fetching mapped PCM device and card indexes (versus one that returns a card and PCM device pair [array]) > > > > 4. Removed some jack controls (enable/disable) from soc-usb > > > > 5. Updated documentation for #3 > > > > > > Those are the major changes that will come in the next revision. I'm just trying to figure out who/where the "protocol version" should be checked if we decided to add it. (or if we need to check for it anywhere...) From the userspace perspective, it should be agnostic to how we've implemented offloading from the kernel, and I don't see any major shifts in how userspace implements things even if we make improvements from kernel. > > > Hi Takashi, > > Could you possibly help share some direction on what you think of the current design, and if you think its detrimental that we make modifications mentioned by Cezary? I have the next revision ready for review, but I wanted to get a better sense on the likeliness of this landing upstream w/o the major modifications. Honestly speaking, I have no big preference about that design question. The most important thing is rather what's visible change to users. An advantage of the current design (sort of add-on to the existing USB-audio driver) is that it's merely a few card controls that are added and visible, and the rest is just as of now. The remaining design issue (two cards or single card) is rather kernel-internal, and has nothing to do with users. So I'm fine with the current design. OTOH, if we follow the pattern of HD-audio, at least there will be more preliminary changes in USB-audio driver side like we've done for HD-audio. That is, make most of USB-audio code to be usable as (a kind of) library code. It's more work, but certainly doable. And if that can be achieved and there other similar use cases of this stuff not only from Qualcomm, it might make sense to go in that way, too. That said, it's rather a question about what's extended in future. If Intel will need / want to move on that direction, too, that's a good reason to reconsider the basic design. thanks, Takashi
On 12/10/2024 7:18 AM, Cezary Rojewski wrote: > On 2024-12-06 1:28 AM, Wesley Cheng wrote: >> >> On 12/4/2024 2:01 PM, Cezary Rojewski wrote: >>> On 2024-12-03 9:38 PM, Wesley Cheng wrote: >>>> Hi Cezary, >>>> >>>> On 12/3/2024 8:17 AM, Cezary Rojewski wrote: > > ... > >>>>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >>>>> >>>> >>>> Just to clarify, "struct snd_soc_usb" does have some correlation with our "codec" entity within the QCOM ASoC design. This would be the q6usb driver. >>>> >>>> >>>>> Currently struct snd_soc_usb does not represent any component at all. Lack of codec representative, component representative and, given my current understanding, mixed dependency of sound/usb on sound/soc/soc-usb does lead to hard-to-understand ASoC solution. >>>> >>>> >>>> IMO the dependency on USB SND is necessary, so that we can leverage all the pre-existing sequences used to identify USB audio devices, and have some ability to utilize USB HCD APIs as well within the offload driver. >>> >>> So, while I do not have patches in shape good enough to be shared, what we have in mind is closer to existing HDAudio solution and how it is covered in both ALSA and ASoC. >>> >>> A ASoC sound card is effectively a combination of instances of struct snd_soc_component. Think of it as an MFD device. Typically at least two components are needed: >>> >>> - platform component, e.g.: for representing DSP-capable device >>> - codec component, e.g.: for representing the codec device >>> >>> USB could be represented by such a component, listed as a dependency of a sound card. By component I literally mean it extending the base struct: >>> >>> stuct snd_soc_usb { >>> struct snd_soc_component base; >>> (...) >>> }; >>> >>> In my opinion HDAudio is a good example of how to mesh existing ALSA-based implementation with ASoC. Full, well implemented behaviour of HDAudio codec device drivers is present at sound/pci/hda/patch_*.c and friends. That part of devoid of any ASoC members. At the same time, an ASoC wrapper is present at sound/soc/codecs/hda.c. It will represent each and every HDAudio codec device on the HDAudio bus as a ASoC-component. This follows the ASoC design and thus is easy understand for any daily ASoC user, at least in my opinion. >>> >>> Next, the USB Audio Offload streams are a limited resource but I do not see a reason to not treat it as a pool. Again, HDAudio comes into picture. The HDAudio streams are assigned and released with help of HDAudio library, code found in sound/hda/hdac_stream.c. In essence, as long as UAOL-capable streaming is allowed, a pcm->open() could approach a UAOL-lib (? component perhaps?) and perform ->assign(). If no resources available, fallback to the non-offloaded case. >>> >>> While I have not commented on the kcontrol part, the above means that our current design does go into a different direction. We'd like to avoid stream-assignment hardcoding i.e.: predefining who owns a UAOL-capable stream if possible. >>> >>> >> >> Thanks for sharing the implementation for HDA. I did take a look to the best of my ability on how the HDAudio library was built, and I see the differences that are there with the current proposal. However, I think modifying the current design to something like that would also require the QCOM ASoC side to change a bit too. As mentioned by Pierre, I think its worthwhile to see if we can get the initial changes in, which is the major part of the challenge. For the most part, I think we could eventually refactor soc-usb to behave similarly to what hda_bind.c is doing. Both entities are the ones that handle linking (or creation in case of HDA) of ASoC components. The one major factor I can see is that within the HDA implementation vs USB SND is that, for USB, hot plugging is a common practice, and that's a scenario that will probably need more discussion if we do make that shift. >> >> >> Anyway, I just wanted to acknowledge the technical details that are utilized by HDAudio, and that we could potentially get there with USB SoC as well. > > Hello, > > > After analyzing the USB for some time to get an even better understanding of what's present in this series, I arrived at a conclusion that indeed, the approach present here clearly differs from what I would call _by the book_ approach for hardware-based USB Audio offloading. > > All sections below refer to the public xHCI spec [1]. > A high-level bullets for the probing procedure: > > 1. xHCI root and resources probe() as they do today > 2. xHCI reads HCCPARAMS2 (section 5.3.9) and checks GSC bit > 2a. If GSC==0, the UAOL enumeration halts > > 3. xHCI sends GET_EXTPROP_TRB with ECI=1 to retrieve capabilities supported (section 4.6.17 and Table 4-3) > 3a. If AUDIO_SIDEBAND bit is not set, the UAOL enumeration halts > > 4. Create a platform_device instance. This instance will act as a bridge between USB and ASoC world. For simplicity, let's call it usb-component, a representative of USB in struct snd_soc_component. > > 5. On the platform_device->probe() the device requests information about resources available from xHCI (section 7.9.1.1), ECI=1, SubType=001 > 6. Allocate a list of streams per device or list per endpoint supported based on the data retrieved with the followup TRB of SubType=010. > Hi Cezary, Ah...this is why I mentioned earlier if what you were talking about was the XHCI audio sideband feature mentioned in the xHCI spec, which this series is not. What you are mentioning is a full HW offload of audio transfers, and that system memory is not utilized for those transfers. In this case, we're just offloading the work, ie handling of data transfers, to an audio DSP. This is what Mathias and I clarified on the below discussion: https://lore.kernel.org/linux-usb/17890837-f74f-483f-bbfe-658b3e8176d6@linux.intel.com/ > (things get more complicated here, stopping) > > Now, any time a sound card with bound usb-component would begin PCM operation, starting with substream->open(), the component would first check if the device and/or the endpoint has resources necessary to support offloading. If not, it would fallback to the non-offloaded case. > > > I do not see implementation for any TRBs I mentioned above here. The HCCPARAMS2 seem to be ignored too. At the same time, I'm unsure about the "interrupters" piece. I believe they make the approach present here somehow work, yet may not be required by the _by the book_ approach at all. > > IMO, the xHCI spec doesn't really go over the audio sideband implementation in detail, so its hard to evaluate what a proper design is to accommodate for it. I've heard that there was work done on the Windows OS to support this, but other than a brief mention of it, there were no implementation details either. In this series, the proposal is that the apps/main core is still responsible for handling the control interfaces and power management, and only offloading the handling and completion of transfers. Thanks Wesley Cheng
On 12/10/2024 8:40 AM, Takashi Iwai wrote: > On Tue, 10 Dec 2024 01:59:10 +0100, > Wesley Cheng wrote: >> On 12/5/2024 4:53 PM, Wesley Cheng wrote: >>> On 12/4/2024 2:49 PM, Pierre-Louis Bossart wrote: >>>>>>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >>>>>> The main difference is that we don’t want the USB audio *control* part to be seen in two places. The only requirement is to stream data with an alternate optimized path, but all the volume control and whatnot is supposed to be done using the regular usb-audio card. It would be complete chaos for userspace if the same volume can be represented differently. >>>>>> The comparison with HDaudio is not quite right either. In the case of HDaudio, it’s an all-or-nothing solution. The external device is controlled by one entity, either legacy or ASoC based. That choice is made at driver probe time. In the case of USB, the application needs to have the choice of using either the legacy path, or the optimized path that goes through a DSP. I think the last thing you want given this context is to make the USB audio device an ASoC codec. >>>>>> I find it rather interesting that this architectural feedback comes at the v30, it’s unfair to Wesley really... >>>>> Hi Pierre, >>>>> >>>>> Obviously I'm late. After scanning the history of this one, indeed it's been a while since v1 has been sent. And thus I posted no NACKs. At the same time if I am to choose between: provide feedback vs provide no-feedback, I'd rather choose the former even if I'm to be ignored/overridden by a subsystem maintainer. >>>>> >>>>> The subsystem maintainers also hold the last word, and I have no problem with them merging the patches if they believe its existing shape is good-enough. For example, my team could follow up this implementation next year with a patchset expanding/updating the functionality. I see this as a viable option. >>>> That’s what we had in mind before I left Intel. The interfaces seen by userspace are PCM devices and kcontrols, it doesn’t matter too much if there is one card, two cards, and if the implementation relies on an ASoC codec, a library or something else. >>>> The bulk of the work is to enable the USB offload from top to bottom, by changing PipeWire/CRAS/HAL to select the new optimized path when available and deal with plug/unplug events. >>>> Improvements at the kernel level can be done later if required. It’s hard to argue that the proposal in this series is fundamentally broken, but as usual it’s likely that some requirements are missing or not known yet. The same thing happened with compressed offload, none one thought about gapless playback until Android made it a requirement. Maybe what we’d need is a ‘protocol version’ for USB offload so that changes can be tracked and handled? >>> Thanks for chiming in, Pierre. So for now, with the next revision I have prepared, I'm currently adding: >>> >>> 1. Some improvements to xHCI sideband to account for core sequences that need to be notified to the offload driver, ie transfer ring free >>> >>> 2. Moved the USB SND offload mixer driver into the QC vendor module for now, as instructed by Takashi: >>> >>> https://lore.kernel.org/linux-usb/87cyiiaxpc.wl-tiwai@suse.de/ >>> >>> 3. Added separate kcontrols for fetching mapped PCM device and card indexes (versus one that returns a card and PCM device pair [array]) >>> >>> 4. Removed some jack controls (enable/disable) from soc-usb >>> >>> 5. Updated documentation for #3 >>> >>> >>> Those are the major changes that will come in the next revision. I'm just trying to figure out who/where the "protocol version" should be checked if we decided to add it. (or if we need to check for it anywhere...) From the userspace perspective, it should be agnostic to how we've implemented offloading from the kernel, and I don't see any major shifts in how userspace implements things even if we make improvements from kernel. >> >> Hi Takashi, >> >> Could you possibly help share some direction on what you think of the current design, and if you think its detrimental that we make modifications mentioned by Cezary? I have the next revision ready for review, but I wanted to get a better sense on the likeliness of this landing upstream w/o the major modifications. > Honestly speaking, I have no big preference about that design > question. The most important thing is rather what's visible change to > users. An advantage of the current design (sort of add-on to the > existing USB-audio driver) is that it's merely a few card controls > that are added and visible, and the rest is just as of now. The > remaining design issue (two cards or single card) is rather > kernel-internal, and has nothing to do with users. So I'm fine with > the current design. > > OTOH, if we follow the pattern of HD-audio, at least there will be > more preliminary changes in USB-audio driver side like we've done for > HD-audio. That is, make most of USB-audio code to be usable as (a > kind of) library code. It's more work, but certainly doable. And if > that can be achieved and there other similar use cases of this stuff > not only from Qualcomm, it might make sense to go in that way, too. > That said, it's rather a question about what's extended in future. > If Intel will need / want to move on that direction, too, that's a > good reason to reconsider the basic design. > So to clarify, what Cezary and I are proposing are actually two different concepts to achieve some sort of offloading for audio data. In my use case, we're trying to leverage as much of the USB SND implementation as possible, and only offloading the handling of audio transfers. Everything else is still handled by USB SND, hence the reason for it being an add-on since most of it stays the same. Unfortunately, I don't have any details about the full HW offload design, as public material on it is fairly minimal. So it would be difficult for me to rework my series to something I don't have a line of sight into. Personally (and as you can probably tell :)), I would prefer if we could do the refactoring in stages (if actually required), since I've been pushing this method for awhile now, and I'm not sure if I can take up that effort to do that on my next submission. At least from the QC perspective if we did move to the HDaudio-type implementation, I think I'd need to also change up the ASoC design we have currently implemented as well, so it wouldn't be a trivial change. Thanks Wesley Cheng
> On 12/10/2024 8:40 AM, Takashi Iwai wrote: >> On Tue, 10 Dec 2024 01:59:10 +0100, >> Wesley Cheng wrote: >>> On 12/5/2024 4:53 PM, Wesley Cheng wrote: >>> Hi Takashi, >>> >>> Could you possibly help share some direction on what you think of the current design, and if you think its detrimental that we make modifications mentioned by Cezary? I have the next revision ready for review, but I wanted to get a better sense on the likeliness of this landing upstream w/o the major modifications. >> >> Honestly speaking, I have no big preference about that design >> question. The most important thing is rather what's visible change to >> users. An advantage of the current design (sort of add-on to the >> existing USB-audio driver) is that it's merely a few card controls >> that are added and visible, and the rest is just as of now. The >> remaining design issue (two cards or single card) is rather >> kernel-internal, and has nothing to do with users. So I'm fine with >> the current design. >> >> OTOH, if we follow the pattern of HD-audio, at least there will be >> more preliminary changes in USB-audio driver side like we've done for >> HD-audio. That is, make most of USB-audio code to be usable as (a >> kind of) library code. It's more work, but certainly doable. And if >> that can be achieved and there other similar use cases of this stuff >> not only from Qualcomm, it might make sense to go in that way, too. >> That said, it's rather a question about what's extended in future. >> If Intel will need / want to move on that direction, too, that's a >> good reason to reconsider the basic design. >> > > So to clarify, what Cezary and I are proposing are actually two different concepts to achieve some sort of offloading for audio data. In my use case, we're trying to leverage as much of the USB SND implementation as possible, and only offloading the handling of audio transfers. Everything else is still handled by USB SND, hence the reason for it being an add-on since most of it stays the same. Unfortunately, I don't have any details about the full HW offload design, as public material on it is fairly minimal. So it would be difficult for me to rework my series to something I don't have a line of sight into. Personally (and as you can probably tell :)), I would prefer if we could do the refactoring in stages (if actually required), since I've been pushing this method for awhile now, and I'm not sure if I can take up that effort to do that on my next submission. At least from the QC perspective if we did move to the HDaudio-type implementation, I think I'd need to also > change up the ASoC design we have currently implemented as well, so it wouldn't be a trivial change. > > > Thanks > > Wesley Cheng > Given that the series has already undergone extensive review, I prefer Wesley's design. We've begun leveraging the design in our local environment with positive results. Furthermore, we've proposed an additional feature to enable USB audio offload during system suspend [1]. In brief, by combining these two points, we can identify use cases where other vendors could also benefit from Wesley's design. [1] https://patchwork.kernel.org/project/linux-usb/cover/20241106083501.408074-1-guanyulin@google.com/ Regards, Guan-Yu
On 12/10/24 9:18 AM, Cezary Rojewski wrote: > On 2024-12-06 1:28 AM, Wesley Cheng wrote: >> >> On 12/4/2024 2:01 PM, Cezary Rojewski wrote: >>> On 2024-12-03 9:38 PM, Wesley Cheng wrote: >>>> Hi Cezary, >>>> >>>> On 12/3/2024 8:17 AM, Cezary Rojewski wrote: > > ... > >>>>> UAOL is one of our priorities right now and some (e.g.: me) prefer to not pollute their mind with another approaches until what they have in mind is crystalized. In short, I'd vote for a approach where USB device has a ASoC representative in sound/soc/codecs/ just like it is the case for HDAudio. Either that or at least a ASoC-component representative, a dependency for UAOL-capable card to enumerate. >>>>> >>>> >>>> Just to clarify, "struct snd_soc_usb" does have some correlation with our "codec" entity within the QCOM ASoC design. This would be the q6usb driver. >>>> >>>> >>>>> Currently struct snd_soc_usb does not represent any component at all. Lack of codec representative, component representative and, given my current understanding, mixed dependency of sound/usb on sound/soc/soc-usb does lead to hard-to-understand ASoC solution. >>>> >>>> >>>> IMO the dependency on USB SND is necessary, so that we can leverage all the pre-existing sequences used to identify USB audio devices, and have some ability to utilize USB HCD APIs as well within the offload driver. >>> >>> So, while I do not have patches in shape good enough to be shared, what we have in mind is closer to existing HDAudio solution and how it is covered in both ALSA and ASoC. >>> >>> A ASoC sound card is effectively a combination of instances of struct snd_soc_component. Think of it as an MFD device. Typically at least two components are needed: >>> >>> - platform component, e.g.: for representing DSP-capable device >>> - codec component, e.g.: for representing the codec device >>> >>> USB could be represented by such a component, listed as a dependency of a sound card. By component I literally mean it extending the base struct: >>> >>> stuct snd_soc_usb { >>> struct snd_soc_component base; >>> (...) >>> }; >>> >>> In my opinion HDAudio is a good example of how to mesh existing ALSA-based implementation with ASoC. Full, well implemented behaviour of HDAudio codec device drivers is present at sound/pci/hda/patch_*.c and friends. That part of devoid of any ASoC members. At the same time, an ASoC wrapper is present at sound/soc/codecs/hda.c. It will represent each and every HDAudio codec device on the HDAudio bus as a ASoC-component. This follows the ASoC design and thus is easy understand for any daily ASoC user, at least in my opinion. >>> >>> Next, the USB Audio Offload streams are a limited resource but I do not see a reason to not treat it as a pool. Again, HDAudio comes into picture. The HDAudio streams are assigned and released with help of HDAudio library, code found in sound/hda/hdac_stream.c. In essence, as long as UAOL-capable streaming is allowed, a pcm->open() could approach a UAOL-lib (? component perhaps?) and perform ->assign(). If no resources available, fallback to the non-offloaded case. >>> >>> While I have not commented on the kcontrol part, the above means that our current design does go into a different direction. We'd like to avoid stream-assignment hardcoding i.e.: predefining who owns a UAOL-capable stream if possible. >>> >>> >> >> Thanks for sharing the implementation for HDA. I did take a look to the best of my ability on how the HDAudio library was built, and I see the differences that are there with the current proposal. However, I think modifying the current design to something like that would also require the QCOM ASoC side to change a bit too. As mentioned by Pierre, I think its worthwhile to see if we can get the initial changes in, which is the major part of the challenge. For the most part, I think we could eventually refactor soc-usb to behave similarly to what hda_bind.c is doing. Both entities are the ones that handle linking (or creation in case of HDA) of ASoC components. The one major factor I can see is that within the HDA implementation vs USB SND is that, for USB, hot plugging is a common practice, and that's a scenario that will probably need more discussion if we do make that shift. >> >> >> Anyway, I just wanted to acknowledge the technical details that are utilized by HDAudio, and that we could potentially get there with USB SoC as well. > > Hello, > > > After analyzing the USB for some time to get an even better understanding of what's present in this series, I arrived at a conclusion that indeed, the approach present here clearly differs from what I would call _by the book_ approach for hardware-based USB Audio offloading. > > All sections below refer to the public xHCI spec [1]. > A high-level bullets for the probing procedure: > > 1. xHCI root and resources probe() as they do today > 2. xHCI reads HCCPARAMS2 (section 5.3.9) and checks GSC bit > 2a. If GSC==0, the UAOL enumeration halts > > 3. xHCI sends GET_EXTPROP_TRB with ECI=1 to retrieve capabilities supported (section 4.6.17 and Table 4-3) > 3a. If AUDIO_SIDEBAND bit is not set, the UAOL enumeration halts > > 4. Create a platform_device instance. This instance will act as a bridge between USB and ASoC world. For simplicity, let's call it usb-component, a representative of USB in struct snd_soc_component. > > 5. On the platform_device->probe() the device requests information about resources available from xHCI (section 7.9.1.1), ECI=1, SubType=001 > 6. Allocate a list of streams per device or list per endpoint supported based on the data retrieved with the followup TRB of SubType=010. > > (things get more complicated here, stopping) > > Now, any time a sound card with bound usb-component would begin PCM operation, starting with substream->open(), the component would first check if the device and/or the endpoint has resources necessary to support offloading. If not, it would fallback to the non-offloaded case. It's not really a fallback in the mutually exclusion sense. Even if the resources are present, the non-offloaded path shall always be usable. > I do not see implementation for any TRBs I mentioned above here. The HCCPARAMS2 seem to be ignored too. At the same time, I'm unsure about the "interrupters" piece. I believe they make the approach present here somehow work, yet may not be required by the _by the book_ approach at all. There are clearly platform-specific differences in the way the offloaded resources are exposed. The public xHCI spec may not be enough to describe all cases, and the interrupt mechanism is different as well. The xHCI spec also only tells whether offloaded is possible at a high-level, but there are additional dependencies on DSP firmware/topology to expose those streams. In other words, when those extended bits are not set then offload if not possible, but if they are there's still a number of dependencies that need to be checked.
Requesting to see if we can get some Acked-By tags, and merge on usb-next. Several Qualcomm based chipsets can support USB audio offloading to a dedicated audio DSP, which can take over issuing transfers to the USB host controller. The intention is to reduce the load on the main processors in the SoC, and allow them to be placed into lower power modes. There are several parts to this design: 1. Adding ASoC binding layer 2. Create a USB backend for Q6DSP 3. Introduce XHCI interrupter support 4. Create vendor ops for the USB SND driver USB | ASoC -------------------------------------------------------------------- | _________________________ | |sm8250 platform card | | |_________________________| | | | | ___V____ ____V____ | |Q6USB | |Q6AFE | | |"codec" | |"cpu" | | |________| |_________| | ^ ^ ^ | | |________| | ___V____ | | |SOC-USB | | ________ ________ | | | |USB SND |<--->|QC offld|<------------>|________| | |(card.c)| | |<---------- | |________| |________|___ | | | ^ ^ | | | ____________V_________ | | | | | |APR/GLINK | __ V_______________V_____ | | | |______________________| |USB SND (endpoint.c) | | | | ^ |_________________________| | | | | ^ | | | ___________V___________ | | | |->|audio DSP | ___________V_____________ | | |_______________________| |XHCI HCD |<- | |_________________________| | Adding ASoC binding layer ========================= soc-usb: Intention is to treat a USB port similar to a headphone jack. The port is always present on the device, but cable/pin status can be enabled/disabled. Expose mechanisms for USB backend ASoC drivers to communicate with USB SND. Create a USB backend for Q6DSP ============================== q6usb: Basic backend driver that will be responsible for maintaining the resources needed to initiate a playback stream using the Q6DSP. Will be the entity that checks to make sure the connected USB audio device supports the requested PCM format. If it does not, the PCM open call will fail, and userspace ALSA can take action accordingly. Introduce XHCI interrupter support ================================== XHCI HCD supports multiple interrupters, which allows for events to be routed to different event rings. This is determined by "Interrupter Target" field specified in Section "6.4.1.1 Normal TRB" of the XHCI specification. Events in the offloading case will be routed to an event ring that is assigned to the audio DSP. Create vendor ops for the USB SND driver ======================================== qc_audio_offload: This particular driver has several components associated with it: - QMI stream request handler - XHCI interrupter and resource management - audio DSP memory management When the audio DSP wants to enable a playback stream, the request is first received by the ASoC platform sound card. Depending on the selected route, ASoC will bring up the individual DAIs in the path. The Q6USB backend DAI will send an AFE port start command (with enabling the USB playback path), and the audio DSP will handle the request accordingly. Part of the AFE USB port start handling will have an exchange of control messages using the QMI protocol. The qc_audio_offload driver will populate the buffer information: - Event ring base address - EP transfer ring base address and pass it along to the audio DSP. All endpoint management will now be handed over to the DSP, and the main processor is not involved in transfers. Overall, implementing this feature will still expose separate sound card and PCM devices for both the platform card and USB audio device: 0 [SM8250MTPWCD938]: sm8250 - SM8250-MTP-WCD9380-WSA8810-VA-D SM8250-MTP-WCD9380-WSA8810-VA-DMIC 1 [Audio ]: USB-Audio - USB Audio Generic USB Audio at usb-xhci-hcd.1.auto-1.4, high speed This is to ensure that userspace ALSA entities can decide which route to take when executing the audio playback. In the above, if card#1 is selected, then USB audio data will take the legacy path over the USB PCM drivers, etc... The current limitation is that the latest USB audio device that is identified will be automatically selected by the Q6USB BE DAI for offloading. Future patches can be added to possibly add for more flexibility, but until the userpace applications can be better defined, having these mechanisms will complicate the overall implementation. USB offload Kcontrols ===================== Part of the vendor offload package will have a mixer driver associated with it (mixer_usb_offload.c). This entity will be responsible for coordinating with SOC USB and the Q6USB backend DAI to fetch information about the sound card and PCM device indices associated with the offload path. The logic is done based on the current implementation of how paths are controlled within the QC ASoC implementation. QC ASoC Q6Routing ----------------- Within the Q6 ASOC design, the registered ASoC platform card will expose a set of kcontrols for enabling the BE DAI links to the FE DAI link. For example: tinymix -D 0 contents Number of controls: 1033 ctl type num name value ... 1025 BOOL 1 USB Mixer MultiMedia1 Off 1026 BOOL 1 USB Mixer MultiMedia2 Off 1027 BOOL 1 USB Mixer MultiMedia3 Off 1028 BOOL 1 USB Mixer MultiMedia4 Off 1029 BOOL 1 USB Mixer MultiMedia5 Off 1030 BOOL 1 USB Mixer MultiMedia6 Off 1031 BOOL 1 USB Mixer MultiMedia7 Off 1032 BOOL 1 USB Mixer MultiMedia8 Off Each of these kcontrols will enable the USB BE DAI link (q6usb) to be connected to a FE DAI link (q6asm). Since each of these controls are DAPM widgets, when it is enabled, the DAPM widget's "connect" flag is updated accordingly. USB Offload Mapping ------------------- Based on the Q6routing, the USB BE DAI link can determine which sound card and PCM device is enabled for offloading. Fetching the ASoC platform sound card's information is fairly straightforward, and the bulk of the work goes to finding the corresponding PCM device index. As mentioned above, the USB BE DAI can traverse the DAPM widgets to find the DAPM path that is related to the control for the "USB Mixer." Based on which "USB Mixer" is enabled, it can find the corresponding DAPM widget associated w/ the FE DAI link (Multimedia*). From there it can find the PCM device created for the Multimedia* stream. Only one BE DAI link can be enabled per FE DAI. For example, if the HDMI path is enabled for Multimedia1, the USB Mixer will be disabled and switched over. Examples of kcontrol -------------------- tinymix -D 0 contents Number of controls: 1033 ctl type num name ... 1025 BOOL 1 USB Mixer MultiMedia1 Off 1026 BOOL 1 USB Mixer MultiMedia2 On 1027 BOOL 1 USB Mixer MultiMedia3 Off 1028 BOOL 1 USB Mixer MultiMedia4 Off 1029 BOOL 1 USB Mixer MultiMedia5 Off 1030 BOOL 1 USB Mixer MultiMedia6 Off 1031 BOOL 1 USB Mixer MultiMedia7 Off 1032 BOOL 1 USB Mixer MultiMedia8 Off tinymix -D 2 contents Number of controls: 7 ctl type num name value 0 INT 2 Playback Channel Map 0, 0 (range 0->36) 1 BOOL 2 MDR-1ADAC Playback Switch On, On 2 BOOL 1 MDR-1ADAC Playback Switch On 3 INT 2 MDR-1ADAC Playback Volume 127, 127 (range 0->127) 4 INT 1 MDR-1ADAC Playback Volume 127 (range 0->127) 5 BOOL 1 Sony Internal Clock Validity On 6 INT 2 USB Offload Playback Route PCM#0 0, 1 (range -1->255) The example highlights that the userspace/application can utilize the offload path for the USB device on card#0 PCM device#1. When dealing with multiple USB audio devices, only the latest USB device identified is going to be selected for offload capable. tinymix -D 1 contents Number of controls: 9 ctl type num name value 0 INT 2 Capture Channel Map 0, 0 (range 0->36) 1 INT 2 Playback Channel Map 0, 0 (range 0->36) 2 BOOL 1 Headset Capture Switch On 3 INT 1 Headset Capture Volume 1 (range 0->4) 4 BOOL 1 Sidetone Playback Switch On 5 INT 1 Sidetone Playback Volume 4096 (range 0->8192) 6 BOOL 1 Headset Playback Switch On 7 INT 2 Headset Playback Volume 20, 20 (range 0->24) 8 INT 2 USB Offload Playback Route PCM#0 -1, -1 (range -1->255) "-1, -1" shows that this device has no route to the offload path. This feature was validated using: - tinymix: set/enable the multimedia path to route to USB backend - tinyplay: issue playback on platform card Changelog -------------------------------------------- Changes in v30: - Rebased to usb-next tip - Renamed the xhci-sideband driver to xhci-sec-intr to avoid confusion with the xHCI audio sideband feature mentioned within the spec. - Squashed the xhci-sec-intr change to set IMOD for secondary interrupters into the main patch that introduces the overall driver. Changes in v29: - Fixed some phrases/wording within the SOC USB documentation, and also added an output with aplay -l for the example output. - Fixed allocated string buffer for creating the USB SND offload mixer, and added a PCM index check to ensure that the pcm index is less than the expected number. - Added a complement enable jack call if USB backend DAI link drivers need access to it. Changes in v28: - Updated comments and commit log in the stop endpoint sync patch. Clarified that the default stop endpoint completion routine won't fully run as expected since it has a completion associated w/ the command. - Added a null check for sb->xhci within xhci_sideband_create_interrupter(). This is to just ensure that caller has registered sideband before calling create interrupter. Changes in v27: - Added some comments and notes about the offload design. Enforcing the q6routing to only allow one USB mixer (PCM device) to be enabled at a time. - Modified SND_JACK_USB notifications for all USB audio offloadable devices plugged in - Rebased on latest XHCI secondary interrupter IMOD changes upstream. Modified the change in this series to allow for XHCI sideband to set the IMOD for sideband clients. - Updated documentation on how USB SND kcontrols are involved in the overall design. - Remove mutex locking from suspend/resume platform ops, as USB core ensures that the interface and device are in the RPM_ACTIVE state while disconnect is handled. Changes in v26: - Cleaned up drivers based on errors from checkpatch - Fixed several typos using codespell - Removed any vendor specific notation from USB SND offload mixer patch Changes in v25: - Cleanups on typos mentioned within the xHCI layers - Modified the xHCI interrupter search if clients specify interrupter index - Moved mixer_usb_offload into its own module, so that other vendor offload USB modules can utilize it also. - Added support for USB audio devices that may have multiple PCM streams, as previous implementation only assumed a single PCM device. SOC USB will be able to handle an array of PCM indexes supported by the USB audio device. - Added some additional checks in the QC USB offload driver to check that device has at least one playback stream before allowing to bind - Reordered DT bindings to fix the error found by Rob's bot. The patch that added USB_RX was after the example was updated. - Updated comments within SOC USB to clarify terminology and to keep it consistent - Added SND_USB_JACK type for notifying of USB device audio connections Changes in v24: - Simplified the kcontrols involved in determining how to utilize the offload path. - There is one kcontrol registered to each USB audio device that will output which card/pcm device it is mapped to for the offload route. - Removed kcontrols to track offload status and device selection. - Default to last USB audio device plugged in as offload capable. - kcontrol will reside on USB SND device. - Reworked the tracking of connected USB devices from the Q6USB BE DAI link. Previously, it was convoluted by doing it over an array, but moved to using a list made it much simpler. Logic is still unchanged in that the last USB headset plugged in will be selected for offloading. - Updated the USB SOC RST documentation accordingly with new kcontrol updates. - Added logic to fetch mapped ASoC card and pcm device index that the offload path is mapped to for the USB SND kcontrol (for offload route). - Re-ordered series to hopefully make reviews more readable by combining patches based on the layer modified (ie QC ASoC, ASoC, USB sound, and USB XHCI). Changes in v23: - Added MODULE_DESCRIPTION() fields to drivers that needed it. Changes in v22: - Removed components tag for the ASoC platform card, as the USB SND kcontrol for notifying userspace of offload capable card achieves similar results. - Due to the above, had to remove the review-by tag for the RST documentation, as changes were made to remove the components tag section. - Took in feedback to make the SOC USB add/remove ports void. - Fixed an issue w/ the USB SND kcontrol management for devices that have multi UAC interfaces. (would attempt to create the kcontrol more than once) - Modified SOC USB card and PCM index select to be based off the num_supported streams that is specified by the USB BE DAI. - Modified comments on selecting the latest USB headset for offloading. Changes in v21: - Added an offload jack disable path from the ASoC platform driver and SOC USB. - Refactored some of the existing SOC USB context look up APIs and created some new helpers to search for the USB context. - Renamed snd_soc_usb_find_format to snd_soc_usb_find_supported_format - Removed some XHCI sideband calls that would allow clients to actually enable the IRQ line associated w/ the secondary interrupter. This is removed because there are other dependencies that are required for that to happen, which are not covered as part of this series, and to avoid confusion. - Due to the above, removed the need to export IMOD setting, and enable/disable interrupter APIs. Changes in v20: - Fixed up some formatting changes pointed out in the usb.rst - Added SB null check during XHCI sideband unregister in case caller passes improper argument (xhci_sideband_unregister()) Changes in v19: - Rebased to usb-next to account for some new changes in dependent drivers. Changes in v18: - Rebased to usb-next, which merged in part of the series. Removed these patches. - Reworked Kconfigs for the ASoC USB related components from QCOM Q6DSP drivers to keep dependencies in place for SoC USB and USB SND. - Removed the repurposing of the stop ep sync API into existing XHCI operations. This will be solely used by the XHCI sideband for now. Changes in v17: - Fixed an issue where one patch was squashed into another. - Re-added some kconfig checks for helpers exposed in USB SND for the soc usb driver, after running different kconfigs. Changes in v16: - Modified some code layer dependencies so that soc usb can be split as a separate module. - Split the kcontrols from ASoC QCOM common layer into a separate driver - Reworked SOC USB kcontrols for controlling card + pcm offload routing and status so that there are individual controls for card and pcm devices. - Added a kcontrol remove API in SOC USB to remove the controls on the fly. This required to add some kcontrol management to SOC USB. - Removed the disconnect work and workqueue for the QC USB offload as it is not required, since QMI interface driver ensures events are handled in its own WQ. Changes in v15: - Removed some already merged XHCI changes - Separated SOC USB driver from being always compiled into SOC core. Now configurable from kconfig. - Fixed up ASoC kcontrol naming to fit guidelines. - Removed some unnecessary dummy ifdefs. - Moved usb snd offload capable kcontrol to be initialized by the platform offloading driver. Changes in v14: - Cleaned up some USB SND related feedback: - Renamed SNDUSB OFFLD playback available --> USB offload capable card - Fixed locking while checking if stream is in use - Replaced some mutex pairs with guard(mutex) Changes in v13: - Pulled in secondary/primary interrupter rework from Mathias from: https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/drivers/usb/host?h=fix_eventhandling - Did some cleanup and commit message updates, and tested on current code base. - Added mutex locking to xhci sideband to help prevent any race conditions, esp. for when accessing shared references. - Addressed concerns from Hillf about gfp_flags and locking used in qc_usb_audio_offload. - Rebased onto usb-next Changes in v12: - Updated copyright year to 2024. Happy new years! - Fixed newline format on mixer offload driver. Changes in v11: - Modified QMI format structures to be const Changes in v10: - Added new mixer for exposing kcontrol for sound card created by USB SND. This allows for applications to know which platform sound card has offload support. Will return the card number. - Broke down and cleaned up some functions/APIs within qc_audio_offload driver. - Exported xhci_initialize_ring_info(), and modified XHCI makefile to allow for the XHCI sideband to exist as a module. - Reworked the jack registration and moved it to the QCOM platform card driver, ie sm8250. - Added an SOC USB API to fetch a standard component tag that can be appended to the platform sound card. Added this tag to sm8250 if any USB path exists within the DT node. - Moved kcontrols that existed in the Q6USB driver, and made it a bit more generic, so that naming can be standardized across solutions. SOC USB is now responsible for creation of these kcontrols. - Added a SOC USB RST document explaining some code flows and implementation details so that other vendors can utilize the framework. - Addressed a case where USB device connection events are lost if usb offload driver (qc_audio_offload) is not probed when everything else has been initialized, ie USB SND, SOC USB and ASoC sound card. Add a rediscover device call during module init, to ensure that connection events will be propagated. - Rebased to usb-next. Changes in v9: - Fixed the dt binding check issue with regards to num-hc-interrupters. Changes in v8: - Cleaned up snd_soc_usb_find_priv_data() based on Mark's feedback. Removed some of the duplicate looping code that was present on previous patches. Also renamed the API. - Integrated Mathias' suggestions on his new sideband changes: https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters - Addressed some of Mathias' fixme tags, such as: - Resetting transfer ring dequeue/enqueue pointers - Issuing stop endpoint command during ep removal - Reset ERDP properly to first segment ring during interrupter removal. (this is currently just being cleared to 0, but should be pointing to a valid segment if controller is still running. Changes in v7: - Fixed dt check error for q6usb bindings - Updated q6usb property from qcom,usb-audio-intr-num --> qcom,usb-audio-intr-idx - Removed separate DWC3 HC interrupters num property, and place limits to XHCI one. - Modified xhci_ring_to_sgtable() to use assigned IOVA/DMA address to fetch pages, as it is not ensured event ring allocated is always done in the vmalloc range. Changes in v6: - Fixed limits and description on several DT bindings (XHCI and Q6USB) - Fixed patch subjects to follow other ALSA/ASoC notations. USB SND - Addressed devices which expose multiple audio (UAC) interfaces. These devices will create a single USB sound card with multiple audio streams, and receive multiple interface probe routines. QC offload was not properly considering cases with multiple probe calls. - Renamed offload module name and kconfig to fit within the SND domain. - Renamed attach/detach endpoint API to keep the hw_params notation. Changes in v5: - Removed some unnecessary files that were included - Fixed some typos mentioned - Addressed dt-binding issues and added hc-interrupters definition to usb-xhci.yaml XHCI: - Moved secondary skip events API to xhci-ring and updated implementation - Utilized existing XHCI APIs, such as inc_deq and xhci_update_erst_dequeue() USB SND - Renamed and reworked the APIs in "sound: usb: Export USB SND APIs for modules" patch to include suggestions to utilize snd_usb_hw_params/free and to avoid generic naming. - Added a resume_cb() op for completion sake. - Addressed some locking concerns with regards to when registering for platform hooks. - Added routine to disconnect all offloaded devices during module unbind. ASoC - Replaced individual PCM parameter arguments in snd_soc_usb_connect() with new snd_soc_usb_device structure to pass along PCM info. - Modified snd_jack set report to notify HEADPHONE event, as we do not support record path. Changes in v4: - Rebased to xhci/for-usb-next - Addressed some dt-bindings comments XHCI: - Pulled in latest changes from Mathias' feature_interrupters branch: https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters - Fixed commit text and signage for the XHCI sideband/interrupter related changes - Added some logic to address the FIXME tags mentioned throughout the commits, such as handling multi segment rings and building the SGT, locking concerns, and ep cleanup operations. - Removed some fixme tags for conditions that may not be needed/addressed. - Repurposed the new endpoint stop sync API to be utilized in other places. - Fixed potential compile issue if XHCI sideband config is not defined. ASoC: - Added sound jack control into the Q6USB driver. Allows for userspsace to know when an offload capable device is connected. USB SND: - Avoided exporting _snd_pcm_hw_param_set based on Takashi's recommendation. - Split USB QMI packet header definitions into a separate commit. This is used to properly allow the QMI interface driver to parse and route QMI packets accordingly - Added a "depends on" entry when enabling QC audio offload to avoid compile time issues. Changes in v3: - Changed prefix from RFC to PATCH - Rebased entire series to usb-next - Updated copyright years XHCI: - Rebased changes on top of XHCI changes merged into usb-next, and only added changes that were still under discussion. - Added change to read in the "num-hc-interrupters" device property. ASoC: - qusb6 USB backend - Incorporated suggestions to fetch iommu information with existing APIs - Added two new sound kcontrols to fetch offload status and offload device selection. - offload status - will return the card and pcm device in use tinymix -D 0 get 1 --> 1, 0 (offload in progress on card#1 pcm#0) - device selection - set the card and pcm device to enable offload on. Ex.: tinymix -D 0 set 1 2 0 --> sets offload on card#2 pcm#0 (this should be the USB card) USB SND: - Fixed up some locking related concerns for registering platform ops. - Moved callbacks under the register_mutex, so that - Modified APIs to properly pass more information about the USB SND device, so that the Q6USB backend can build a device list/map, in order to monitor offload status and device selection. Changes in v2: XHCI: - Replaced XHCI and HCD changes with Mathias' XHCI interrupter changes in his tree: https://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git/log/?h=feature_interrupters Adjustments made to Mathias' changes: - Created xhci-intr.h to export/expose interrupter APIs versus exposing xhci.h. Moved dependent structures to this file as well. (so clients can parse out information from "struct xhci_interrupter") - Added some basic locking when requesting interrupters. - Fixed up some sanity checks. - Removed clearing of the ERSTBA during freeing of the interrupter. (pending issue where SMMU fault occurs if DMA addr returned is 64b - TODO) - Clean up pending events in the XHCI secondary interrupter. While testing USB bus suspend, it was seen that on bus resume, the xHCI HC would run into a command timeout. - Added offloading APIs to xHCI to fetch transfer and event ring information. ASoC: - Modified soc-usb to allow for multiple USB port additions. For this to work, the USB offload driver has to have a reference to the USB backend by adding a "usb-soc-be" DT entry to the device saved into XHCI sysdev. - Created separate dt-bindings for defining USB_RX port. - Increased APR timeout to accommodate the situation where the AFE port start command could be delayed due to having to issue a USB bus resume while handling the QMI stream start command. Mathias Nyman (1): xhci: sec-intr: add initial api to register a secondary interrupter entity Wesley Cheng (29): usb: host: xhci: Repurpose event handler for skipping interrupter events usb: host: xhci-mem: Cleanup pending secondary event ring events usb: host: xhci-mem: Allow for interrupter clients to choose specific index usb: host: xhci-plat: Set XHCI max interrupters if property is present usb: dwc3: Specify maximum number of XHCI interrupters ALSA: Add USB audio device jack type ALSA: usb-audio: Export USB SND APIs for modules ALSA: usb-audio: Check for support for requested audio format ALSA: usb-audio: Save UAC sample size information ALSA: usb-audio: Prevent starting of audio stream if in use ASoC: Add SOC USB APIs for adding an USB backend ASoC: usb: Add PCM format check API for USB backend ASoC: usb: Create SOC USB SND jack kcontrol ASoC: usb: Fetch ASoC card and pcm device information ASoC: doc: Add documentation for SOC USB ASoC: dt-bindings: qcom,q6dsp-lpass-ports: Add USB_RX port ASoC: dt-bindings: Update example for enabling USB offload on SM8250 ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp ASoC: qcom: qdsp6: q6afe: Increase APR timeout ASoC: qcom: qdsp6: Add USB backend ASoC driver for Q6 ASoC: qcom: qdsp6: Add headphone jack for offload connection status ASoC: qcom: qdsp6: Fetch USB offload mapped card and PCM device ALSA: usb-audio: Introduce USB SND platform op callbacks ALSA: usb-audio: qcom: Add USB QMI definitions ALSA: usb-audio: qcom: Introduce QC USB SND offloading support ALSA: usb-audio: qcom: Don't allow USB offload path if PCM device is in use ALSA: usb-audio: Add USB offload route kcontrol ALSA: usb-audio: Allow for rediscovery of connected USB SND devices ASoC: usb: Rediscover USB SND devices on USB port add .../bindings/sound/qcom,sm8250.yaml | 15 + Documentation/sound/soc/index.rst | 1 + Documentation/sound/soc/usb.rst | 491 ++++ drivers/usb/dwc3/core.c | 12 + drivers/usb/dwc3/core.h | 2 + drivers/usb/dwc3/host.c | 3 + drivers/usb/host/Kconfig | 11 + drivers/usb/host/Makefile | 2 + drivers/usb/host/xhci-mem.c | 31 +- drivers/usb/host/xhci-plat.c | 2 + drivers/usb/host/xhci-ring.c | 54 +- drivers/usb/host/xhci-sec-intr.c | 439 ++++ drivers/usb/host/xhci.c | 2 +- drivers/usb/host/xhci.h | 14 +- .../sound/qcom,q6dsp-lpass-ports.h | 1 + include/linux/mod_devicetable.h | 2 +- include/linux/usb/xhci-sec-intr.h | 70 + include/sound/jack.h | 4 +- include/sound/q6usboffload.h | 20 + include/sound/soc-usb.h | 147 ++ include/uapi/linux/input-event-codes.h | 3 +- sound/core/jack.c | 6 +- sound/soc/Kconfig | 10 + sound/soc/Makefile | 2 + sound/soc/qcom/Kconfig | 15 + sound/soc/qcom/Makefile | 2 + sound/soc/qcom/qdsp6/Makefile | 1 + sound/soc/qcom/qdsp6/q6afe-dai.c | 60 + sound/soc/qcom/qdsp6/q6afe.c | 194 +- sound/soc/qcom/qdsp6/q6afe.h | 36 +- sound/soc/qcom/qdsp6/q6dsp-lpass-ports.c | 23 + sound/soc/qcom/qdsp6/q6dsp-lpass-ports.h | 1 + sound/soc/qcom/qdsp6/q6routing.c | 32 +- sound/soc/qcom/qdsp6/q6usb.c | 391 ++++ sound/soc/qcom/sm8250.c | 24 +- sound/soc/qcom/usb_offload_utils.c | 56 + sound/soc/qcom/usb_offload_utils.h | 30 + sound/soc/soc-usb.c | 369 +++ sound/usb/Kconfig | 25 + sound/usb/Makefile | 4 +- sound/usb/card.c | 106 + sound/usb/card.h | 17 + sound/usb/endpoint.c | 1 + sound/usb/format.c | 1 + sound/usb/helper.c | 1 + sound/usb/mixer_usb_offload.c | 102 + sound/usb/mixer_usb_offload.h | 17 + sound/usb/pcm.c | 104 +- sound/usb/pcm.h | 11 + sound/usb/qcom/Makefile | 2 + sound/usb/qcom/qc_audio_offload.c | 1974 +++++++++++++++++ sound/usb/qcom/usb_audio_qmi_v01.c | 863 +++++++ sound/usb/qcom/usb_audio_qmi_v01.h | 164 ++ 53 files changed, 5915 insertions(+), 55 deletions(-) create mode 100644 Documentation/sound/soc/usb.rst create mode 100644 drivers/usb/host/xhci-sec-intr.c create mode 100644 include/linux/usb/xhci-sec-intr.h create mode 100644 include/sound/q6usboffload.h create mode 100644 include/sound/soc-usb.h create mode 100644 sound/soc/qcom/qdsp6/q6usb.c create mode 100644 sound/soc/qcom/usb_offload_utils.c create mode 100644 sound/soc/qcom/usb_offload_utils.h create mode 100644 sound/soc/soc-usb.c create mode 100644 sound/usb/mixer_usb_offload.c create mode 100644 sound/usb/mixer_usb_offload.h create mode 100644 sound/usb/qcom/Makefile create mode 100644 sound/usb/qcom/qc_audio_offload.c create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.c create mode 100644 sound/usb/qcom/usb_audio_qmi_v01.h