Hi David, On 03.04.2013 12:15, David Henningsson wrote: > Just to get your attention here on what seems to be an USB audio > regression. > > The bug is described in detail here: > > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1136110?comments=all > > Quoting the bug: > > " > This bug seems to affect only a certain kind of hardware, which is > called "Asynchronous USB Digital Audio Codec (DAC)". It's said that such > a DAC hosts the clock itself (USB Device Host). An ordinary DAC, so > called "Synchronous USB DAC", uses the clock hosted by the mother board, > which is not affected by this bug. > > When this bug affects an asynchronous USB DAC, the audio played by the > DAC is constantly interrupted. The playback itself does not stop, but > the output becomes discontinous, filling with constant crackling noises, > destroying everything the DAC plays. > " > > According to the bug reporter, which seems to have done quite a bit of > research, this started between 3.8-rc6 and 3.8-rc7 as well as stable > kernels and the bug also lists a few commits which could be the cause, > none under sound/usb though. There were no relevant changes for snd-usb between the two versions mentioned. The only patches that come in mind in this time window are: 3e619d041 "USB: EHCI: fix bug in scheduling periodic split transfers" b09a61cc0 "USB: EHCI: fix for leaking isochronous data" And they have both been back-ported to stable. Copied Alan for reference. Any chance some of the bug reporters could try and revert exactly those for testing? Thanks, Daniel _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
