<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Strong noise (unintelligible) when playing through the analog output using mmap" href="https://bugs.freedesktop.org/show_bug.cgi?id=87202#c7">Comment # 7</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Strong noise (unintelligible) when playing through the analog output using mmap" href="https://bugs.freedesktop.org/show_bug.cgi?id=87202">bug 87202</a> from <a class="email" href="mailto:msanchez@gnome.org" title="Mario Sanchez Prada <msanchez@gnome.org>"> Mario Sanchez Prada</a> <pre>After so much testing and gdb debugging today I finally identified the problem in alsa-lib, after following the lead from the experiment mentioned in "Note 1", and it seems to be caused by the call to snd_pcm_mmap_begin() returning the wrong memory chunks in the areas array, leading to the strange noise mentioned. With that in mind, I started looking inside of alsa-lib, and found significant differences between the latest code in the 0.28 release and the one I've available in my environment, which is quite older (0.25). And even better, I found that just upgrading to that newer version of alsa-lib would get rid of the noise, so indeed it seems the problem was there! I've devoted a bit more of time to try to find the specific changeset and it seems that the the fix for <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED NOTOURBUG - Resume from suspend triggers assertion" href="show_bug.cgi?id=64299">bug 64299</a> is the one fixing this specific: <a href="http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=f2d39afe6139ab16aa2aeea0f51f32db79ab1262">http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=f2d39afe6139ab16aa2aeea0f51f32db79ab1262</a> I found that commit by simply looking at the changelog and looking for things related to either mmap or rewinds, and then applying it locally to my package as a patch on top, so I'm pretty certain that it fixes the problem. Still, I would appreciate if someone (maybe David, as the author) could comment on whether this makes sense, so we can maybe resolve this bug as a duplicate or invalid.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>