>> >> > >> > below is what the terminate shows when running pcm_avail.c >> > >> > uid=0 gid=1007 at nutshell:/ # alsactl_test >> > min_period_size: 8 frames, dir: 0 >> > Playback hwparams: FIFO size is 8 >> > Hardware PCM card 0 'rsnd-dai.0-dirana3.0' device 0 subdevice 0 >> > Its setup is: >> > stream : PLAYBACK >> > access : RW_INTERLEAVED >> > format : S16_LE >> > subformat : STD >> > channels : 2 >> > rate : 48000 >> > exact rate : 48000 (48000/1) >> > msbits : 16 >> > buffer_size : 4096 >> > period_size : 1024 >> > period_time : 21333 >> > tstamp_mode : NONE >> > period_step : 1 >> > avail_min : 1024 >> > period_event : 0 >> > start_threshold : 1024 >> > stop_threshold : 4096 >> > silence_threshold: 0 >> > silence_size : 0 >> > boundary : 1073741824 >> > appl_ptr : 0 >> > hw_ptr : 0 >> > Playing silence >> > Available: 0, loop iteration: 0 >> > Available: 1024, loop iteration: 1469 >> > Available: 2048, loop iteration: 5609 >> > Available: 3072, loop iteration: 9667 >> > >> > All I got is just the 4 lines. >> >> If your sound card only increment hw_ptr only at interrupt occur, you >> need to increase default_rewind_safeguard from 256 bytes to your >> selected period size > > > No. PulseAudio, in timer-scheduling mode, does not use periods at all. You need to change the driver so that it reports SNDRV_PCM_INFO_BATCH, so that PulseAudio does not try to use this mode. > > >> >> This mean that your sound card won't work with timer scheduling or >> dynamic latency, you can only archieve low latency by decrease period size >> Why do pulseaudio enable timer scheduling when most sound card use IRQ ? > > > Because most broken sound cards driver authors forget to report SNDRV_PCM_INFO_BATCH? > Most driver use irq interrupt , only a few sound cards ( seem less than ten) can report DMA_RESIDUE_GRANULARITY_BURST Why do timer based scheduling enablef by default ? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20150609/45ad9234/attachment.html>
