[Bug 1805079] Re: click/pop noise in the headphone on several lenovo laptops

Hui Wang,

Apologies for the slow reply.

Do you mean that you also have quiet sound after the boot?

Today I upgraded to 4.19.12, and the results seem the same. I'm running
Funtoo Linux with "gentoo-sources" kernel, HDA and the Realtek codec as
modules and plain ALSA with no daemons. I tried to compile them into
the main kernel image, but the results were the same, except that the
LEDs didn't work.

Here are sone more details:

The noise level I hear does not change with the playback volume. It's
stronger when I play something (e.g., with mplayer) or touch the
touchpad.

Without the 0x12 line, alsamixer shows heasphone and speaker controls at
100%, and "alsactl store" has {Headphone,Speaker} Playback
{Volume,Switch}. Under the standard kernel (with your patch), the
aforementioned controls in alsamixer show up as "00" in a box, and
alsactl has only "Line Out Playback Volume" (and the two Switches). Is
it possible that "line out" is treated differently from "headphone" by
the hardware, or is it just a name?

With the standard kernel, the output of "alsactl store" is identical
whether the sound is in the "too quiet" state or in the "noisy
headphone" state.

Sometimes after I warm-reboot from a standard kernel to a kernel without
the 0x12 line, I hear clicks when muting and unmuting the output, or
noise, but they disappear after I play something.

I put my kernel config and alsactl store output under
http://www.vygo.net/hda/ but I don't know if it aids debugging in any
way. Do you think it may help if I try your kernel config?

Thank you for your efforts and, if appropriate, merry Christmas.

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https://bugs.launchpad.net/bugs/1805079

Title:
click/pop noise in the headphone on several lenovo laptops

Status in linux package in Ubuntu:
Fix Committed

Bug description:
[Impact]
Lenovo told us that some linux uers reported headphone noise on Lenovo's
website. After investigating, we found those Lenovo laptop mdoels all
have the codec of alc285, and we can reproduce the noise problem too.

[Fix]
Don't use the DAC of headphone, let headphone share the DAC with speaker,
the noise disappears.

[Test Case]
After applying this patch, we tested on Lenovo P52, P72, X1 carbon and X1
Yoda2, no noise anymore

[Regression Potential]
Low. This patch only apply to several lenovo machines, and after applying
this patch, both speaker and headphone still work very well.

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