<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#c8">Comment # 8</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><a href="http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=b0b7d0280f977dee1bbff0a1b4cd0c50068d2371;hp=1cf37d72c4e77fac55f2b1792bdcf12744a5a51a">http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=b0b7d0280f977dee1bbff0a1b4cd0c50068d2371;hp=1cf37d72c4e77fac55f2b1792bdcf12744a5a51a</a> @ -5577,6 +5577,12 @@ int snd_pcm_sw_params_set_avail_min(snd_pcm_t *pcm, snd_pcm_sw_params_t *params, #endif { assert(pcm && params); + /* Fix avail_min if it's below period size. The period_size + * defines the minimal wake-up timing accuracy, so it doesn't + * make sense to set below that. + */ + if (val < pcm->period_size) + val = pcm->period_size; params->avail_min = val; return 0; } seem any value below period size is changed to period size, the hw_ptr of most drivers change by a period when interrupt occur, not all driver can report dma_brust size granularity like snd-hda-intel controller , when data in FIFO below FIFO threshold and trigger DMA transfer , the hw_ptr position is accurate up to DMA brust size which is less than period size (pulseaudio use 4 fragments and 25 ms fragment time ) but dma brust size is about 32 frames</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>