Alan Stern wrote: > On Wed, 31 Jul 2013, James Stone wrote: >> On Wed, Jul 31, 2013 at 4:48 PM, Alan Stern <[email protected]> >> wrote: >>> James, see what happens with this patch. It will print a warning >>> message in the system log every time it detects an underrun, but it >>> won't cause an URB submission failure any more. >> >> OK - I will try it, however, it seems a bit like papering over the >> cracks without really understanding what's causing the error.. > > It seems likely that the error is caused by an SMI taking too much > time. At least, we seem to have ruled out everything else. Besides, > this change has to be made eventually in any case -- underruns can > occur at any time, in principle, and they shouldn't cause the audio > driver to fail.
Well, the failure is a bug in snd-usb-audio: when usb_submit_urb fails, it should report the underrun so that the stream can be stopped and restarted cleanly. This would be done by the snd_pcm_stop() call in endpoint.c which is currently commented out because of locking problems. Regards, Clemens -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
