Re: [Qemu-devel] SDL audio and AIO hogging each other's signals

[Ben Taylor]

---- andrzej zaborowski <address@hidden> wrote: 
> Hi,
>   with QEMU_AUDIO_DRV set to "sdl" and booting from CD-ROM with AIO on
> a Linux host and with SDL 1.2.11, qemu locks up in sigwait() (the main
> thread) and SDL_SemWait() (the audio thread) as soon as music is
> playing and CD-ROM is being read at the same time. It appears that
> audio/sdlaudio.c:sdl_callback is called by SDL when it shouldn't be
> called, and block-raw.c is trying to flush the AIO operations, so it
> would seem that the SIGUSR2 which is intended to wake up the sigwait
> is instead captured by SDL and SDL tries to be smart and calls
> sdl_callback. sdl_callback has a sanity check but this check is
> *after* SDL_SemWait() so it is not triggered. The strange thing is
> that using a different signal (tried SIGUSR1 and SIGPOLL) for AIO
> doesn't help. Does SDL catch all signals?
> I could be totally wrong because I don't know SDLAudio at all.
> 
> Any ideas about the exact reason why this is happening and how to fix it?

On Solaris 10/11 x86, I was seeing a bunch of semphore errors emitted
from SDL when using SDL audio.

I'll track this down and report back.

Ben