diff mbox series

[2/2] ucm: docs: Add IVEchoData

Message ID 20230824213312.1258499-2-cujomalainey@chromium.org (mailing list archive)
State New, archived
Headers show
Series [1/2] ucm: docs: Add EchoReferenceDev | expand

Commit Message

Curtis Malainey Aug. 24, 2023, 9:33 p.m. UTC 
From: Curtis Malainey <cujomalainey@chromium.org>

Provide a UCM value to mark devices which are needed to be opened only
for HW purposes but should not be consumed for userspace.

Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
---
 include/use-case.h | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Jaroslav Kysela Aug. 26, 2023, 11:31 a.m. UTC | #1 
On 24. 08. 23 23:33, cujomalainey@chromium.org wrote:
> From: Curtis Malainey <cujomalainey@chromium.org>
> 
> Provide a UCM value to mark devices which are needed to be opened only
> for HW purposes but should not be consumed for userspace.

It would be probably better to describe this in the standard ALSA PCM API than 
UCM. If the device is special, applications without UCM should be also allowed 
to identify them.

				Jaroslav
Curtis Malainey Aug. 31, 2023, 5:06 p.m. UTC | #2 
Curtis Malainey | Chrome OS Audio Senior Software Engineer |
cujomalainey@google.com | Sound Open Firmware Lead


On Sat, Aug 26, 2023 at 4:31 AM Jaroslav Kysela <perex@perex.cz> wrote:
>
> On 24. 08. 23 23:33, cujomalainey@chromium.org wrote:
> > From: Curtis Malainey <cujomalainey@chromium.org>
> >
> > Provide a UCM value to mark devices which are needed to be opened only
> > for HW purposes but should not be consumed for userspace.
>
> It would be probably better to describe this in the standard ALSA PCM API than
> UCM. If the device is special, applications without UCM should be also allowed
> to identify them.
>
>                                 Jaroslav

Would something like an additional device class and a format subclass
be acceptable?

Curtis
Jaroslav Kysela Aug. 31, 2023, 7:59 p.m. UTC | #3 
On 31. 08. 23 19:06, Curtis Malainey wrote:
> Curtis Malainey | Chrome OS Audio Senior Software Engineer |
> cujomalainey@google.com | Sound Open Firmware Lead
> 
> 
> On Sat, Aug 26, 2023 at 4:31 AM Jaroslav Kysela <perex@perex.cz> wrote:
>>
>> On 24. 08. 23 23:33, cujomalainey@chromium.org wrote:
>>> From: Curtis Malainey <cujomalainey@chromium.org>
>>>
>>> Provide a UCM value to mark devices which are needed to be opened only
>>> for HW purposes but should not be consumed for userspace.
>>
>> It would be probably better to describe this in the standard ALSA PCM API than
>> UCM. If the device is special, applications without UCM should be also allowed
>> to identify them.
>>
>>                                  Jaroslav
> 
> Would something like an additional device class and a format subclass
> be acceptable?

The device class extension sounds good.

I don't know details for the format extension - does app require to set 
hw_params ? If yes, is the goal to prevent standard applications to set the 
hw_params ? If no, the format bitmask may be set to zero, thus hw_params will 
always fail.

					Jaroslav
diff mbox series

Patch

diff --git a/include/use-case.h b/include/use-case.h
index 3c7c0a26..3d629667 100644
--- a/include/use-case.h
+++ b/include/use-case.h
@@ -387,6 +387,12 @@  int snd_use_case_get_list(snd_use_case_mgr_t *uc_mgr,
  *	  device with the same parameters it opens the source device with.
  *   - EDIDFile
  *      - Path to EDID file for HDMI devices
+ *   - IVDataEcho
+ *      - Used only on devices pointed to by EchoReferenceDev. Used to mark
+ *        references that might be lower quality (e.g. reduced bit depth) as
+ *        they are intended for a HW feature and not userspace consumption.
+ *        These PCMs still need to be opened by userspace but are not
+ *        recommended for consumption.
  *   - JackCTL
  *      - jack control device name
  *   - JackControl