sound broken in qemu 0.12.x

[SergK]

In qemu 0.12.x there is a jitter when sound is played by guest Windows XP SP2. Also there are warnings on console:

alsa: Unexpected state 1
alsa: Unexpected state 1

and qemu tries to eat 100% cpu. According to strace it polls alsa device continuously:

futex(0x849e60, FUTEX_WAKE_PRIVATE, 1) = 1
select(23, [6 10 12 20 22], [18], [], {1, 0}) = 1 (out [18], left {0, 999997})
poll([{fd=18, events=POLLOUT|POLLERR|POLLNVAL}], 1, 0) = 1 ([{fd=18, revents=POLLOUT|POLLERR}])
write(2, "alsa: "..., 6) = 6
write(2, "Unexpected state 1\n"..., 19) = 19

The bug appears with ac97 and es1370 guest sound devices (i didn't test others).

With OSS host sound driver there are no warnings and consumption of cpu by qemu is normal, but jitter in the sound is still there.

[SergK (sergk)]

P.S. qemu 0.11.1 works perfectly in the same situation

[Dustin Kirkland  (kirkland)]

I'm curious if you've tried the pa (pulseaudio) sound driver?

[SergK (sergk)]

I'v tried pulseaudio. There is no problem with it. Sound is clear and cpu consumption is normal.
But with sdl driver sound is worse than with alsa or oss and there are such warnings:

A bug was just triggered in audio_run_out
Context:
audio: played=1024 sw->total_hw_samples_mixed=1022
A bug was just triggered in audio_run_out
Context:
audio: played=2044 sw->total_hw_samples_mixed=1024

[Dustin Kirkland  (kirkland)]

Anthony, can you reproduce this?

I use pulseaudio here, and it works well.

[Anthony Liguori (anthony-codemonkey)]

Best thing to do is send a note to qemu-devel CC'ing the audio maintainer (malc <email address hidden>).

[Dustin Kirkland  (kirkland)]

SergK- I recommend you send that email, as pulseaudio is the
recommended sound driver for Ubuntu, and that seems to be working here
well for me. Thanks.

[Michael Tokarev (mjt+launchpad-tls)]

Isn't it the case that's fixed by commit d9812b033a17c82f9e933757c1c3ef364e3ba62d as shown in http://comments.gmane.org/gmane.comp.emulators.qemu/72593 which is actually this very bugreport mirrored to qemu-devel mailinglist?

[Michael Tokarev (mjt+launchpad-tls)]

More information about this. The mentioned commit fixes just the messages apparently, but not the actual problem which is elsewhere. The complete fix consists of 3 patches: the above in comment#7, and also 22d948a2d97434192018bdabaf0a50cda7f994be and 38cc9b607f85017b095793cab6c129bc9844f441 from qemu-kvm git tree (both applies and applicable for 0.12 as well as 0.13).