potential bug or quirk in the linux kernel usb subsystem, usb microphone sampling rate resolution rate

Hello Mr. Kroah-Hartman,



my name is Hans Paliege and i am a longtime Linux user, but i came=20
across a potential peculiar quirk or bug in the usb subsystem

that may need your attention. According to the kernel documentation i=20
should contact You as the main developer directly.



I am using a debian unstable amd64 build that is updated daily, and=20
during boot for about two weeks now

the audio frequency sample rate of my logitech C270 usb webcam is no=20
longer initialized correctly.

As a result the webcam only delivers video but no audio. The webcam=20
microphone is as a audio device recognized

by the webbrowser but the input is null.



During boot the dmesg error messages are:


[ +0,007125] usb 3-1: current rate 24000 is different from the runtime=20
rate 16000
[ +0,002572] usb 3-1: 3:3: cannot set freq 24000 to ep 0x82



After manual usbreset of the logitech C270 webcam the dmesg error=20
messages are:


[M=C3=A4r 2 22:13] usb 3-6.2: reset full-speed USB device number 7 using x=
hci_hcd
[ +12,959814] usb 3-1: reset high-speed USB device number 2 using xhci_hcd
[ +0,288046] uvcvideo 3-1:1.0: Found UVC 1.00 device C270 HD WEBCAM=20
(046d:0825)
[ +0,036940] usb 3-1: current rate 16000 is different from the runtime=20
rate 32000
[ +0,063995] usb 3-1: current rate 24000 is different from the runtime=20
rate 16000
[ +0,061679] usb 3-1: 3:3: cannot set freq 24000 to ep 0x82
[ +0,213449] usb 3-1: set resolution quirk: cval->res =3D 384




After some internet search i could not find any specific command,=20
application or grub boot parameter to manually set the rate to the=20
runtime rate of 16000 or 32000.

The quirk seems to be, that the sampling rate is automatically set to=20
the value of 24000, while the actual working runtime rates are ignored.


Any subsequent pipewire-alsa related audio volume and input/output works=
=20
fine, and i have to use a really old ZOOM H2 usb microphone at 44100=20
that works for now.




Maybe a recent change in the linux kernel or the usb subsytem caused=20
this. It would be great if you could take a closer look at it and fix it.



Thank you very much.


Best regards

Hans Paliege