[alsa-devel] Constant noise on HDA ALC275

[David Henningsson]

On 10/08/2012 10:34 PM, Julien Danjou wrote:
>> Hm, then maybe the effect of removing noise appears no matter which
>> input of NID 0x0b be unmuted?
>
> I've retested some, and you're right, it seems some others do make the
> noise disappear:
>
> For example, this works too:
>
> @@ -198,7 +198,7 @@
>     Control: name="Beep Playback Switch", index=0, device=0
>       ControlAmp: chs=3, dir=In, idx=4, ofs=0
>     Amp-In caps: ofs=0x17, nsteps=0x1f, stepsize=0x05, mute=1
> -  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80]
> +  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x00 0x00] [0x80 0x80] [0x80 0x80]
>     Connection: 5
>        0x18 0x19 0x1a 0x1b 0x1d
>   Node 0x0c [Audio Mixer] wcaps 0x20010b: Stereo Amp-In
>
>
> This one too:
> @@ -198,7 +198,7 @@
>     Control: name="Beep Playback Switch", index=0, device=0
>       ControlAmp: chs=3, dir=In, idx=4, ofs=0
>     Amp-In caps: ofs=0x17, nsteps=0x1f, stepsize=0x05, mute=1
> -  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80]
> +  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x00 0x00] [0x80 0x80]
>     Connection: 5
>        0x18 0x19 0x1a 0x1b 0x1d
>   Node 0x0c [Audio Mixer] wcaps 0x20010b: Stereo Amp-In
>
> Other pairs do not work, but some do change the noise sound.

So; if everything is muted, it causes some codec bug to appear. If this 
only happens in the speaker, maybe we should try to reroute the speaker 
to go 0x02 -> 0x0c -> 0x14 instead of 0x03 -> 0x0d -> 0x14? What will 
happen if you change 0x14 to take its input from 0x0c instead?


-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic