[alsa-devel] [PATCH] ALSA: hda - Disable AA-loopback on ALC668
tiwai at suse.de
Tue May 20 18:15:31 CEST 2014
At Tue, 20 May 2014 18:06:53 +0200,
Takashi Iwai wrote:
> At Tue, 20 May 2014 17:59:30 +0200,
> Gabriele Mazzotta wrote:
> > On Thursday 15 May 2014 21:56:23, Gabriele Mazzotta <gabriele.mzt at gmail.com>
> > wrote:
> > > On Wednesday 14 May 2014 16:31:13, Gabriele Mazzotta
> > <gabriele.mzt at gmail.com> wrote:
> > > I'm sorry, I was wrong. This patch does not help. I'm still trying to
> > > understand what temporarily fixed the problem, I was quite sure this patch
> > did
> > > it, but all of the sudden the noise came back. I'm still trying to find the
> > > real cause, but I doubt I'll succeed.
> > >
> > > Regards,
> > > Gabriele
> > I have to correct myself again, the first patch I submitted is working, I'm
> > sorry. However, it seems that disabling the AA-loopback path is not necessary,
> > muting the input 0x0b in node 0x0c (as it was suggested here:
> > https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1252733/comments/26) is enough to get rid of the white noise.
> This reminds me of a similar problem reported on Sony VAIO.
> The codec is different, it's ALC275, though.
> > What is the proper way to fix this problem?
> Just to be sure: does the mic input itself work correctly?
> Maybe the easiest fix would be disabling the aamix, indeed.
> But you shouldn't apply it generically to ALC668. I'm sure that it's
> pretty specific to machines, not codec chips. So, create a fixup
> function that matches with your machine instead.
Or, another hackish solution is to override the connection list of the
mixer widget. Point the item to another (e.g. non-existing) node, so
that the parser won't pick it up.
For this (and even with your patch to disable aamix completely), the
fixup should have a static init verb to mute this mixer input.
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