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

[Ikjoon Jang]

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.

>
>
> Takashi