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

On Wed, Mar 04, 2026 at 07:55:13PM +0100, Hans Jörg Paliege wrote:
> Hello Mr. Kroah-Hartman,
> 
> 
> 
> my name is Hans Paliege and i am a longtime Linux user, but i came across a
> potential peculiar quirk or bug in the usb subsystem
> 
> that may need your attention. According to the kernel documentation i should
> contact You as the main developer directly.

The documentation should say to contact the linux-usb list, which I've
 cc:ed here :)

> I am using a debian unstable amd64 build that is updated daily, and during
> boot for about two weeks now
> 
> the audio frequency sample rate of my logitech C270 usb webcam is no longer
> initialized correctly.

When did it last work properly?  When did it stop working?  Any specific
kernel version ranges?

> As a result the webcam only delivers video but no audio. The webcam
> microphone is as a audio device recognized
> by the webbrowser but the input is null.

Those are 2 different USB devices in one, so something is off for the
audio stream somehow.

> 
> During boot the dmesg error messages are:
> 
> 
> [ +0,007125] usb 3-1: current rate 24000 is different from the runtime 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 messages
> are:
> 
> 
> [Mär 2 22:13] usb 3-6.2: reset full-speed USB device number 7 using xhci_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
> (046d:0825)
> [ +0,036940] usb 3-1: current rate 16000 is different from the runtime rate
> 32000
> [ +0,063995] usb 3-1: current rate 24000 is different from the runtime 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 = 384

Is that the audio device, or the video device?

> After some internet search i could not find any specific command,
> application or grub boot parameter to manually set the rate to the runtime
> rate of 16000 or 32000.
> 
> The quirk seems to be, that the sampling rate is automatically set to the
> value of 24000, while the actual working runtime rates are ignored.
> 
> Any subsequent pipewire-alsa related audio volume and input/output works
> fine, and i have to use a really old ZOOM H2 usb microphone at 44100 that
> works for now.
> 
> Maybe a recent change in the linux kernel or the usb subsytem caused this.
> It would be great if you could take a closer look at it and fix it.

A range of kernel versions here would be helpful, as would any other
kernel log messages.

thanks,

greg k-h