Re: [BUG] xhci: repeated URB cancel on UVC status interrupt EP (0x83) loops for ~15s, stalls camera - Intel Cannon Point-LP [8086:9ded]

[Michal Pecio <michal.pecio@gmail.com>]

On Sat, 22 Aug 2026 10:41:27 +0300, Дмитрий wrote:
> The Windows comparison makes the control interesting, but does not
> establish the Linux xHCI mechanism: under the same bright lighting,
> Windows delivered 6.95 fps with Low Light Compensation enabled and
> 29.88 fps with it disabled, followed by 40 successful stream restarts.

I suppose this setting just affects exposure time. Since frame period
can't be shorter than exposure, frame rate sometimes slows down.

At any rate, Windows appears to have no problem with data loss.

> I repeated the 320x240 YUYV, 30 fps test with
> exposure_dynamic_framerate=0 and successfully captured the uvcvideo
> trace=0x400 output this time.
> 
> The run completed with rc=0 and delivered 300 buffers in 31.065
> seconds, corresponding to an effective delivered rate of 9.66 fps.
> There were 620 reported sequence gaps, so only 32.61% of the observed
> sequence positions were delivered.
> 
> Despite the lower resolution, the camera selected exactly the same USB
> streaming configuration as at 640x480:
> 
> Device requested 3072 B/frame bandwidth
> Selecting alternate setting 7 (3072 B/frame bandwidth)
> Allocated 5 URB buffers of 32x3072 bytes each

Try

rmmod uvcvideo
modprobe uvcvideo trace=0x400 quirks=0x80

and then experiment with various video modes.

Regards,
Michal