Alan Stern wrote: > On Fri, 11 Feb 2011, Sarah Sharp wrote: > > I suspect it might be the audio driver, as someone on the alsa mailing > > list suggested the USB sound driver can't handle when one isochronous > > buffer in an URB has an error, but the URB status is 0. > > I don't think that can happen. The URB status won't be 0 unless all > the individual buffers have 0 status. In any case, the driver would then just copy garbage samples out of the buffer; this wouldn't affect the driver's data structures. > > From: Pierre-Louis Bossart <bossart.nospam@xxxxxxxxx> > > > > Note that this is only a work-around, it does not address the > > root cause of this inconsistency between urbs and PCM states. The > > dmesg below shows two calls to snd_urb_complete, the substream is > > NULL and the state is either running or stopped. This doesn't make > > any sense. > > ... > > ALSA urb.c:492: frame 0 active: -84 > > ALSA urb.c:197: cannot submit urb (err = -19) > > ALSA urb.c:186: NULL substream (subs->running 1) <- How is this possible? > > ALSA urb.c:186: NULL substream (subs->running 0) > > It's most likely a matter of the device being disconnected but the > device file still being open. subs->pcm_substream == NULL happens only when the device file _has_ been closed. > Perhaps not everything gets cleaned up the way it should when that > happens. There seems to be a race between snd_usb_pcm_close() and snd_usb_stream_disconnect(). I think a mutex taken by both functions should fix this; and all functions that check 'shutdown' probably need serializing. Regards, Clemens -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
