Re: [PATCH] ALSA: usb-audio: Apply sample rate quirk to Logitech Connect

[Takashi Iwai]

On Mon, 29 Mar 2021 08:23:52 +0200,
Ikjoon Jang wrote:
> 
> On Wed, Mar 24, 2021 at 8:49 PM Takashi Iwai <tiwai@xxxxxxx> wrote:
> >
> > On Wed, 24 Mar 2021 13:03:14 +0100,
> > Ikjoon Jang wrote:
> > >
> > > On Wed, Mar 24, 2021, 7:16 PM Joakim Tjernlund <Joakim.Tjernlund@xxxxxxxxxxxx>
> > > wrote:
> > >
> > >     On Wed, 2021-03-24 at 18:51 +0800, Ikjoon Jang wrote:
> > >     > Logitech ConferenceCam Connect is a compound USB device with UVC and
> > >     > UAC. Not 100% reproducible but sometimes it keeps responding STALL to
> > >     > every control transfer once it receives get_freq request.
> > >     >
> > >     > This patch adds 046d:0x084c to a snd_usb_get_sample_rate_quirk list.
> > >     >
> > >     > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203419
> > >     > Signed-off-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx>
> > >
> > >     Most Logitech USB headset I got needs a delay in snd_usb_ctl_msg_quirk()
> > >     Have you tried to add say 20 ms delay in there?
> > >
> > > I didn't try that. But it sounds reasonable to me.
> > >
> > > let me try that quirk here. If that is the case, HID might need that delay
> > > also. Logitech Group webcam had a similar problem on control xfer of
> > > get_report from an another interface for HID.
> >
> > The Logitech devices with 046d:* should be covered generally in
> > snd_usb_ctl_msg_quirk(), so I guess it's a different problem.
> > But please check it first.
> >
> > > And 20ms can be too long if it's applied to every control transfer. I will
> > > test the device with shorter delay if you didn't try it before.
> >
> > Actually the delay applied to Logitech devices is from 1 to 2ms, not
> > 20ms.  The 20ms delay is applied for some other devices.  But if
> > extending the delay fixes the problem, we need to reconsider the delay
> > length.
> 
> I tested this Logitech device with various delays 2..20ms
> in snd_usb_ctl_msg_quirk() but it didn't help.
> 
> Disregarding the delay between control transfers,
> This device is always stuck at get_cur, responding STALL to all
> control transfers.
> 
> [   24.045618] usb 1-1.2.1.1: 1:1: cannot get freq at ep 0x82
> [   24.167475] usb 1-1.2.1.1: 2:0: cannot get min/max values for
> control 2 (id 2)
> [   24.287393] usb 1-1.2.1.1: 6:0: cannot get min/max values for
> control 2 (id 6)
> [   24.289854] usbcore: registered new interface driver snd-usb-audio
> [   24.877073] usb 1-1.2.1.1: 2:1: usb_set_interface failed (-32)
> 
> And I've also found that in some other platforms (with the same kernel),
> this device fails at get_freq - timeout with NYETs or NAKs (instead of STALL),
> and succeeded in following set_interface even without any delays
> I've tried but couldn't find any differences between the two. ;-(
> 
> So until now, I think this approach of skipping get_rate is the only
> one possible
> workaround for Logitech Connect.

OK, that makes sense, then.  I applied your patch now.

Thanks!


Takashi