Hi Daniel On 03/04/13 17:00, Daniel Mack wrote: > Hi Michael, > > On 03.04.2013 16:11, Michael Trimarchi wrote: >> On 03/04/13 15:55, Michael Trimarchi wrote: >>> 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. > > Is OMAP3 at all a platform that is affected by the bug? It seems the > effect is only seen on some special host controller hardware anyway. > Yes, omap3 ehci and m2tech products is not affected and I'm testing a dac with internal clock. >> Sorry the comment was for a bug that is not included in this list and recently fixed. >> USB: EHCI: fix bug in iTD/siTD DMA pool allocation > > Sorry, you lost me. So what's the status of this issue now? Does "USB: > EHCI: fix bug in iTD/siTD DMA pool allocation" fix it? With or without it, I don't have any choppy audio and this is not a fix of this bug. > > If not - and assuming you can reproduce the bug - which patches of the > two I mentioned did you revert, and what was the effect of that? Did you > try and remove both as well? In my version I have the other two commits applied. I doubt that these two commits are the reason of the choppy audio. What I can do, it test it on my laptop tomorrow and send feedback result Michael > > > Thanks, > Daniel > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
