write(2) lc_r problem

[Mathew Kanner]

On Jan 24, Stefan Ehmann wrote:
> I'm trying to write a small sound application and run across a problem
> on CURRENT.
> 
> It's very basic at the moment. It simply reads pcm data from a file and
> uses write(2) on /dev/dsp.
> 
> But as soon as I link the program with -lc_r there's always about 1
> second delay before a write call - which makes it pretty unusable for
> playing sound.
> 
> It should be easy reproducable if you link audio/waveplay with -lc_r.
> 
> This doesn't happen in either FreeBSD 4.9, Knoppix or CURRENT if linked
> with -lkse or -lthr.
> 
> Am I'm missing something basic when using write together with lc_r or
> ist this a bug in CURRENT?

	There is definetly a bug with the sound code when using vchans
and select.  Make sure that  (using sysctl)

	hw.snd.maxautovchans=0
	hw.snd.pcmX.vchans=0

	--Mat

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