<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - protocol-native: I get endless underruns when I playback when alsa buffer size is small" href="https://bugs.freedesktop.org/show_bug.cgi?id=84878#c6">Comment # 6</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - protocol-native: I get endless underruns when I playback when alsa buffer size is small" href="https://bugs.freedesktop.org/show_bug.cgi?id=84878">bug 84878</a> from <a class="email" href="mailto:prahal@yahoo.com" title="Alban Browaeys <prahal@yahoo.com>"> Alban Browaeys</a> <pre>(In reply to Raymond from <a href="show_bug.cgi?id=84878#c1">comment #1</a>) > seem your sound card support DMA_RESIDUE_GRANULARITY_SEGMENT if the residue > Residue is updated after each successfully completed segment of the transfer > > as your sound card does not have hardware register to count the number of > dma transfer > > <a href="https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/include/">https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/include/</a> > linux/dmaengine.h > > > @DMA_RESIDUE_GRANULARITY_SEGMENT: Residue is updated after each successfully > * completed segment of the transfer (For cyclic transfers this is after > each > * period). This is typically implemented by having the hardware generate an > * interrupt after each transferred segment and then the drivers updates the > * outstanding residue by the size of the segment. Another possibility is if > * the hardware supports scatter-gather and the segment descriptor has a > field > * which gets set after the segment has been completed. The driver then > counts > * the number of segments without the flag set to compute the residue. > * @DMA_RESIDUE_GRANULARITY_BURST: Residue is updated after each transferred > * burst. This is typically only supported if the hardware has a progress > * register of some sort (E.g. a register with the current read/write > address > * or a register with the amount of bursts/beats/bytes that have been > * transferred or still need to be transferred). As of now my only clue regarding this is printk output. (In reply to Raymond from <a href="show_bug.cgi?id=84878#c3">comment #3</a>) > if your sound card can report DMA_RESIDUE_GRANULARITY_BRUST > > > <a href="http://mailman.alsa-project.org/pipermail/alsa-devel/2014-September/081501">http://mailman.alsa-project.org/pipermail/alsa-devel/2014-September/081501</a>. > html > > what is the DMA brust size? I am still looking for this. Sorry for the lag.</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>