ACK / APPLIED[Unstable]: [SRU][B/C/D/unstable][PATCH 0/1] fix the pop noise for lenovo laptops with alc285

[Seth Forshee]

On Tue, Nov 27, 2018 at 10:42:02AM +0800, Hui Wang wrote:
> BugLink: https://bugs.launchpad.net/bugs/1805079
> 
> [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.

Cherry pick from maintainer tree, limited scope, positive testing.

Acked-by: Seth Forshee <seth.forshee at canonical.com>

The patch did not apply to unstable, so I cherry picked the fix
directly. Thanks!