Hi Daniel On 03/04/13 12:23, Daniel Mack wrote: > 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" This last one, doesn't give me any problem, just a memory leak and not a choppy playback (tested on 48Khz, 96Khz, 192Khz 32bit on OMAP3 device) and I don't think that it can be the reason of the problem. http://www.m2tech.biz/hiface_dac.html Michael > > 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 > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
