Re: Regression: webcam freezing since Linux 6.15

[Bart Nagel <bart@tremby.net>]

At 2026-07-30 13:08:14 +0200, Michal Pecio wrote:
> I'm slightly curious what exactly happens there (probably MSE after
> Short Packet on a single-TRB TD), and whether Missed Service Error may
> point at a Link TRB, because the current fix wouldn't handle that and
> the stream could still hang. So your failure rate may actually be
> reduced to 1/255 of what it was, but still not zero.
> 
> If possible, please boot the patched kernel again and run it for
> a little longer. If it fails, post dmesg starting from the "Miss
> service interval error" line which is followed by "All TDs skipped".
> 
> And while that is running, also collect another log:
> 
> cd /sys/kernel/tracing/
> echo 1 > events/xhci-hcd/xhci_handle_event/enable
> echo 1 > tracing_on
> grep -B5 Missed trace_pipe | tee /tmp/trace
> 
> This is supposed to log 6 lines for every Missed Service Error, so it
> will grow, but not terribly fast.

Before I make a bad assumption and collect a useless log, please
confirm for me exactly which debugging I should enable. Just the two
you gave above, or also one or both of the ones I was using before:

    echo "func handle_tx_event +p" >/proc/dynamic_debug/control
    echo 0xff >/sys/module/uvcvideo/parameters/trace

Thanks.