<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - severe underruns with usb audio, works with pa 3.0 - buffer setup seems wrong" href="https://bugs.freedesktop.org/show_bug.cgi?id=86262#c13">Comment # 13</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - severe underruns with usb audio, works with pa 3.0 - buffer setup seems wrong" href="https://bugs.freedesktop.org/show_bug.cgi?id=86262">bug 86262</a> from <a class="email" href="mailto:superquad.vortex2@gmail.com" title="Raymond <superquad.vortex2@gmail.com>"> Raymond</a> <pre>(In reply to David Mansfield from <a href="show_bug.cgi?id=86262#c2">comment #2</a>) > Created <a href="attachment.cgi?id=109438" name="attach_109438" title="force tsched even in "BATCH" mode and on KVM.">attachment 109438</a> <a href="attachment.cgi?id=109438&action=edit" title="force tsched even in "BATCH" mode and on KVM.">[details]</a> <a href='page.cgi?id=splinter.html&bug=86262&attachment=109438'>[review]</a> [review] > force tsched even in "BATCH" mode and on KVM. > > The attached patch fixes the problem by essentially reversing commit > 826c8f69d34ef49e86fe0ab6c93c1ffba8916131 (alsa: Disable timer-scheduling for > PCMs with the BATCH flag). > > Without tsched, the buffers are miniscule and we get overruns constantly. > With tsched (by design) the buffers are huge. > > Not sure what the implications are. > > NOTE: I also forced enablement of tsched on KVM. I'm having the exact same > problem in a VM, and it is MUCH better with the patch although still not > "glitch-free" which it is (with the patch) on bare-metal. > > NOTE: In kvm I am using USB passthrough, not emulated hardware audio device. <a href="http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/modules/alsa/alsa-sink.c?id=53b046d5c9593d848270e85017c2999a61256e0e">http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/modules/alsa/alsa-sink.c?id=53b046d5c9593d848270e85017c2999a61256e0e</a> the patch was designed for those emulated sound card inside vm , this mean that you have to differentiate usb passthrough and emulated sound card</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>