write(2) lc_r problem

[Stefan Ehmann]

On Sat, 2004-01-24 at 21:03, Mathew Kanner wrote:
> On Jan 24, Stefan Ehmann wrote:
> > On Sat, 2004-01-24 at 20:15, Mathew Kanner wrote:
> > > 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
> > 
> > You're right, that fixed it. That's also the reason why it worked on
> > stable (vchans was disabled there).
> 
> 	Please try this untested patch with vchans enabled.
> 

Great, now it also works with vchans enabled.

I'm also testing a pcm patch by truckman@ at the moment. Unfortunately
those two combined don't run nicely.

Panicstring: mutex pcm0:virtual:0 not owned at /usr/src/sys/dev/sound/pcm/channel.c:90