| Message ID | 20211005084436.6812-1-pavel.hofman@ivitera.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 0560c9c552c1815e7b480bc11fd785fefc82bb27 |
| Headers | show |
| Series | [v2] usb: gadget: f_uac2: fixed EP-IN wMaxPacketSize | expand |
On Tue 05 Oct 2021 at 10:44, Pavel Hofman <pavel.hofman@ivitera.com> wrote: > Async feedback patches broke enumeration on Windows 10 previously fixed > by commit 789ea77310f0 ("usb: gadget: f_uac2: always increase endpoint > max_packet_size by one audio slot"). > > While the existing calculation for EP OUT capture for async mode yields > size+1 frame due to uac2_opts->fb_max > 0, playback side lost the +1 > feature. Therefore the +1 frame addition must be re-introduced for > playback. Win10 enumerates the device only when both EP IN and EP OUT > max packet sizes are (at least) +1 frame. > > Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com> > Fixes: e89bb4288378 ("usb: gadget: u_audio: add real feedback > implementation") > Cc: stable@vger.kernel.org > Tested-by: Henrik Enquist <henrik.enquist@gmail.com> > Tested-by: Jack Pham <jackp@codeaurora.org> > --- > drivers/usb/gadget/function/f_uac2.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c > index 17a7ab2c799c..5c7eddf511e5 100644 > --- a/drivers/usb/gadget/function/f_uac2.c > +++ b/drivers/usb/gadget/function/f_uac2.c > @@ -665,11 +665,17 @@ static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts, > ssize = uac2_opts->c_ssize; > } > > - if (!is_playback && (uac2_opts->c_sync == USB_ENDPOINT_SYNC_ASYNC)) > + if (!is_playback && (uac2_opts->c_sync == USB_ENDPOINT_SYNC_ASYNC)) { > + // Win10 requires max packet size + 1 frame Actually it is not really about windows 10, but more about the USB Audio Format specification: see https://www.usb.org/sites/default/files/USB%20Audio%20v3.0_0.zip section 2.3.1.2.1 Windows 10 is just picky about what the SIP size should be. > srate = srate * (1000 + uac2_opts->fb_max) / 1000; > - > - max_size_bw = num_channels(chmask) * ssize * > - DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))); > + // updated srate is always bigger, therefore DIV_ROUND_UP always yields +1 > + max_size_bw = num_channels(chmask) * ssize * > + (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1)))); Doing DIV_ROUND_UP is actually right for if (!is_playback && (uac2_opts->c_sync == USB_ENDPOINT_SYNC_ADAPTIVE)) otherwise, it should be rounded down + 1. I'll reply with my version of the patch to make things more clear > + } else { > + // adding 1 frame provision for Win10 > + max_size_bw = num_channels(chmask) * ssize * > + (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))) + 1); > + } > ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_size_bw, > max_size_ep));
diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c index 17a7ab2c799c..5c7eddf511e5 100644 --- a/drivers/usb/gadget/function/f_uac2.c +++ b/drivers/usb/gadget/function/f_uac2.c @@ -665,11 +665,17 @@ static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts, ssize = uac2_opts->c_ssize; } - if (!is_playback && (uac2_opts->c_sync == USB_ENDPOINT_SYNC_ASYNC)) + if (!is_playback && (uac2_opts->c_sync == USB_ENDPOINT_SYNC_ASYNC)) { + // Win10 requires max packet size + 1 frame srate = srate * (1000 + uac2_opts->fb_max) / 1000; - - max_size_bw = num_channels(chmask) * ssize * - DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))); + // updated srate is always bigger, therefore DIV_ROUND_UP always yields +1 + max_size_bw = num_channels(chmask) * ssize * + (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1)))); + } else { + // adding 1 frame provision for Win10 + max_size_bw = num_channels(chmask) * ssize * + (DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1))) + 1); + } ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_size_bw, max_size_ep));
Async feedback patches broke enumeration on Windows 10 previously fixed by commit 789ea77310f0 ("usb: gadget: f_uac2: always increase endpoint max_packet_size by one audio slot"). While the existing calculation for EP OUT capture for async mode yields size+1 frame due to uac2_opts->fb_max > 0, playback side lost the +1 feature. Therefore the +1 frame addition must be re-introduced for playback. Win10 enumerates the device only when both EP IN and EP OUT max packet sizes are (at least) +1 frame. Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com> Fixes: e89bb4288378 ("usb: gadget: u_audio: add real feedback implementation") Cc: stable@vger.kernel.org Tested-by: Henrik Enquist <henrik.enquist@gmail.com> Tested-by: Jack Pham <jackp@codeaurora.org> --- drivers/usb/gadget/function/f_uac2.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)