More buzzing fun with snd_emu10kx - but now with more determinism!

[Andrew J. Caines]

On 07/11/2010 17:03, Garrett Cooper wrote:
> The problem appears to be with vchan-related code. If I start up 4+
> applications on my machine that access the audio device, all goes
> wonky on the 4+ allocation

I can confirm this behaviour, which seems odd with hw.snd.maxautovchans
defaulting to 16. It does not appear to be affected by increasing
dev.pcm.0.play.vchans up fron the default of 2 (as I apparently did at
some point up to 7.x), though reading sound(4) it's clear I don't fully
understand vchans.

A problem I encountered with snd_emu10kx in a clean 8.1RC2 install which
was not present in any previous version is a faint rapid mechanical
clicking sound adjustable with the "cd" mixer setting.

The only non-default audio setting I have is in loader.conf:

hint.emu10kx.0.multichannel_disabled="1"
hint.emu10kx.1.disabled="1"


pcm0: <EMU10Kx DSP front PCM interface> on emu10kx0
pcm0: <TriTech TR28602 AC97 Codec (id = 0x54524123)>
pcm0: Codec features 5 bit master volume, no 3D Stereo Enhancement

FreeBSD Audio Driver (newpcm: 32bit 2009061500/i386)
Installed devices:
pcm0: <EMU10Kx DSP front PCM interface> on emu10kx0 (4p:2v/1r:1v) default
	snddev flags=0x2e2<AUTOVCHAN,BUSY,MPSAFE,REGISTERED,VPC>
	[pcm0:play:dsp0.p0]: spd 48000, fmt 0x00200010, flags 0x00002100, 
0x00000004
	interrupts 726, underruns 0, feed 5, ready 0 [b:4096/2048/2|bs:4096/2048/2]
	channel flags=0x2100<BUSY,HAS_VCHAN>
...


-- 
-Andrew J. Caines-   Unix Systems Engineer   A.J.Caines at halplant.com
FreeBSD/Linux/Solaris, Web/Mail/Proxy/...   http://halplant.com:2001/
   "Machines take me by surprise with great frequency" - Alan Turing