Re: [Qemu-devel] OSS audio debugging

[malc <malc@pulsesoft.com>]

On Thu, 10 Jun 2004, Leigh Dyer wrote:

> Hi all,
>
> I've been playing with the sb16 emulation using a Win2k guest. The Add
> New Hardware wizard's hardware probe picked it up and installed it
> without any problems, but playing audio quite often resulted in a very
> abrupt end to the emulation.
>
> I've tracked the problem down to the AUD_run() function in oss.c. When
> writing to the card, it calls SNDCTL_DSP_GETOSPACE, which is apparently
> meant to return the amount of data that can be written to the card
> without blocking. However, for some reason, occasionally the value
> returned in abinfo.bytes is negative. This negative value makes it
> through to the write() call, which then fails with an unknown error,
> hitting the:
>
> ERRFail ("write audio");
>
> line.
>
> I really don't know much about OSS, so I'm not sure how this should be
> handled. Does anyone else know what this could mean? For reference, the
> card is an ess1371, running ALSA drivers in OSS emulation mode.

I for one don't know what it means. And while im figuring this out you can
try experimental SDL output driver(but see caveats):
http://www.boblycat.org/~malc/code/patches/qemu/5_aqemu.patch.gz

Caveats:
 a. oss.c must be modified and #define USE_SDL_AUDIO 1 inserted somewhere
    near the top (or #ifdef _WIN32 changed to #if 1)

 b. it was hacked in an hour or so and therefore i can not claim that it
    works all that well, in fact it contains a deadlock

P.S. Can someone on Windows try this?

-- 
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