<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Issue of CPU usage with HiFiBerry driver snd_soc_hifiberry_amp with Debian Wheezy kernel 3.12.28" href="https://bugs.freedesktop.org/show_bug.cgi?id=84585#c21">Comment # 21</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Issue of CPU usage with HiFiBerry driver snd_soc_hifiberry_amp with Debian Wheezy kernel 3.12.28" href="https://bugs.freedesktop.org/show_bug.cgi?id=84585">bug 84585</a> from <a class="email" href="mailto:superquad.vortex2@gmail.com" title="Raymond <superquad.vortex2@gmail.com>"> Raymond</a> <pre><a href="https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/include/linux/dmaengine.h">https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/include/linux/dmaengine.h</a> * @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). */ enum dma_residue_granularity { DMA_RESIDUE_GRANULARITY_DESCRIPTOR = 0, DMA_RESIDUE_GRANULARITY_SEGMENT = 1, DMA_RESIDUE_GRANULARITY_BURST = 2, timer scheduling require at least two hardware feature DMA_RESIDUE_GRANULARITY_BURST and SNDRV_PCM_INFO_NO_PERIOD_WAKEUP <a href="https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/log/?qt=grep&q=period+wakeup">https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/log/?qt=grep&q=period+wakeup</a></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>