Re: pcm & exclusive sleep mutex with Oct19 CURRENT

Hello Paolo,
	See below.

On Oct 20, Paolo Pisati wrote:
> from my dmesg:
> [snip]
> exclusive sleep mutex pcm0:mixer (pcm mixer) r = 0 (0xc2d34540) locked _at_ /usr/src/sys/dev/sound/pcm/mixer.c:322

	Could you try deleting the snd_mtxlock and snd_mtxunlock in
mixer_hwvol_init() in mixer.c?  I think it's uneeded as the function
is only called in particular device instance creation and no-one
should be able touch it yet.

> 
> acquiring duplicate lock of same type: "pcm channel"
>  1st pcm0:record:0 _at_ /usr/src/sys/dev/sound/pcm/sound.c:195
>  2nd pcm0:play:0 _at_ /usr/src/sys/dev/sound/pcm/sound.c:195
> Stack backtrace:

	Please try my "wild guess" patch that is attached.  I tried to
re-arrange the routine to only hold one locked channel at a time.  I
suppose another option would be flag the lock type as having
duplicates ok.

	--Mat

-- 
	If you optimize everything, you will always be unhappy.
			- Don Knuth