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
