[alsa-devel] [PATCH] wss_lib: snd_wss_calibrate_mute improvement

[Takashi Iwai]

At 18 Aug 2008 13:16:56 +0200,
krzysztof.h1 at poczta.fm wrote:
> 
> > At Mon, 18 Aug 2008 10:50:15 +0200,
> > Rene Herman wrote:
> > > 
> > > On 17-08-08 22:38, Krzysztof Helt wrote:
> > > 
> > > > From: Krzysztof Helt <krzysztof.h1 at wp.pl>
> > > > 
> > > > Mute sound by setting mute bit without
> > > > setting volume to 0. It makes both source code
> > > > and binary shorter.
> > > > 
> > > > Signed-off-by: Krzysztof Helt <krzysztof.h1 at wp.pl>
> > > 
> > > Grmmbbled-over-by: Rene Herman <rene.herman at gmail.com>
> > > 
> > > This should be safe and the current function indeed generates crap code
> > 
> > > but in the sense of always expecting the worst broken hardware variants
> > 
> > > to be out there I must say I'd rather have seen that GCC were beter. But
> > 
> > > yes, sure.
> > 
> > Yeah, the slightest concern is the intention of using 0x80 there.
> > If this patch was already tested on some real hardwares (and I guess
> > it should work), I'm willing to apply it.  Krzystof, was this tested
> > on your machines?
> > 
> 
> I have tested it only on cs4236 (inside laptop) and opti931 I have in the old PC at the moment. If you want I can retest on more hardware.
> 
> The second check I noticed that for some registers the volume is defined as gain (so 0 is the least audible) and for some (CS4231_MONO_CTRL, CS4231_LEFT/RIGHT_OUTPUT) is defined as attentuation (the 0 is the most audible). In two cases, the old code set volume to the loudest and mute it with mute bit, probably the opposite what was intended.
> 
> It is not a crucial patch. You may drop it.

Oh, no, your patch is actually a correct fix.

The thing is that I wanted to be sure that this doesn't introduce an
obvious breakage.


Takashi