Excerpts from Takashi Iwai's message of June 14, 2020 5:54 am:
On Sat, 13 Jun 2020 18:25:22 +0200, Alex Xu (Hello71) wrote:
Excerpts from Takashi Iwai's message of June 11, 2020 1:11 pm:
Thanks, so something still missing in the mmap handling, I guess.
I've worked on two different branches for potential fixes of your problems. Could you test topic/dma-fix and topic/dma-fix2 branches? git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git Just pull one of them onto Linus' git HEAD.
I guess we'll go with David's new patch, but still it's interesting whether my changes do anything good actually.
Takashi
On torvalds 623f6dc593, topic/dma-fix causes sound to be output as alternating half-second bursts of noise and a few seconds of silence. topic/dma-fix2 appears to work properly.
OK, thanks for the feedback! Just to make sure, you're using PulseAudio, right? If so, it was still something wrong about mmap, and the secondary method (the fallback to the continuous page) looks like a safer approach in the end.
I suppose that David's fix will be merged sooner or later. Meanwhile I'll work on the change in the sound driver side to make things a bit more robust. They don't conflict and both good applicable.
thanks,
Takashi
Ah, no, I think that wasn't clear. I use ALSA directly with mostly default configuration, except an asym sets separate default playback and record devices.
asound.conf:
defaults.pcm.card 1 defaults.ctl.card 1
pcm.!default { type asym playback.pcm { type plug slave.pcm "dmix" } capture.pcm { type plug slave.pcm { type dsnoop ipc_key 6793 slave.pcm "hw:U0x46d0x81d" } } }
I think I wasn't able to set defaults.pcm.dmix.card and defaults.pcm.dsnoop.card for some reason, not sure why. I can try that, but I don't think it will affect this mmap issue.
Thanks, Alex.