[alsa-devel] [PATCH] ALSA: usb-audio: Don't resubmit pending URBs at MIDI error recovery

[Takashi Iwai]

At Sat, 06 Dec 2014 20:54:48 +0100,
Clemens Ladisch wrote:
> 
> Takashi Iwai wrote:
> > In snd_usbmidi_error_timer(), the driver tries to resubmit MIDI input
> > URBs to reactivate the MIDI stream, but this causes the error when
> > some of URBs are still pending
> 
> I wonder what kept the other URBs alive.

I'm not quite sure, but maybe it's controller-specific issues.
FWIW, the reporter used R-Pi.

> > For avoiding these errors, check the pending URBs and skip
> > resubmitting such ones.
> >
> > Reported-and-tested-by: Stefan Seyfried <stefan.seyfried at googlemail.com>
> > Cc: <stable at vger.kernel.org>
> > Signed-off-by: Takashi Iwai <tiwai at suse.de>
> 
> Anyway,
> Acked-by: Clemens Ladisch <clemens at ladisch.de>

Queued now.


thanks,

Takashi

> > ---
> >  sound/usb/midi.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/sound/usb/midi.c b/sound/usb/midi.c
> > index d3d49525a16b..5bfb695547f8 100644
> > --- a/sound/usb/midi.c
> > +++ b/sound/usb/midi.c
> > @@ -365,6 +365,8 @@ static void snd_usbmidi_error_timer(unsigned long data)
> >  		if (in && in->error_resubmit) {
> >  			in->error_resubmit = 0;
> >  			for (j = 0; j < INPUT_URBS; ++j) {
> > +				if (atomic_read(&in->urbs[j]->use_count))
> > +					continue;
> >  				in->urbs[j]->dev = umidi->dev;
> >  				snd_usbmidi_submit_urb(in->urbs[j], GFP_ATOMIC);
> >  			}
>