Re: [patch] ess maestro, support for hardware volume control

[Zach Brown <zab@zabbo.net>]

> this patch applies to (at least) 2.4.3 up to and including 2.4.6-pre2.
> It enables the hardware volume control feature of the maestro.

cool.  I had support for this in the mega-patch I posted long ago, but
I never seperated and submitted those changes 'cause I'm a moron.

> By giving hwv=0 to insmod one can explicitly disable it. Setting

can we have a better name like 'hwvol_enable'?

> +		set_mixer(c, 0, val);

careful.  you just used the indirect ac97 registers without holding the
card's lock..  if another processor does a mixer ioctl while this is
happening you'll get weird behaviour.

it looks like you should just be able to spin_{,un}lock(card->lock)
around that call, but the maestro locking is so friggin' twisty.. this
gets even more exciting when the driver uses ac97_codec, which the
mega-patch also had in it.

Fix the locking (and the obscure parameter name? :)) and it looks
fine.. good work.

-- 
 zach