[SRU][Artful][OEM][PATCH 0/2] speaker can't output sound anymore after system resumes from S3 on a lenovo machine with alc257

[Hui Wang]

BugLink: https://bugs.launchpad.net/bugs/1758829

The 1st patch is already in the kernel 4.15 and the 2nd patch
is already in the 4.15 stable-queue, so will not send them to bionic
again here.

[Impact]
After booting up, the speaker works well. If we suspend the machine then resume
it back, the speaker can't output sound, even rebooting can't make the speaker
work, we need to power off the machine then power up the machine, the speaker
can work again.

[Fix]
We need to add the basic support for the codec alc257 first (0001-xxx.patch),
then add hooking function for this codec and clear the bit of 15 for register
0x57 (0002-xxx.patch). Both of these two patches come from mainline kernel.

[Test Case]
After booting up the system, suspend the machine, then resume the machine,
test the speaker, the speaker can output sound. Repeat the testing steps many
times, the speaker still can work.

[Regression Potential]
Very low, since the 1st patch just add the support for a new codec alc257, it
will not affect other codecs. The 2nd patch just apply a fix for alc257, it
doesn't affect other codecs too. And both of them come from mainline and
realtek.


Kailang Yang (2):
  ALSA: hda/realtek - New codec support for ALC257
  ALSA: hda/realtek - Fix speaker no sound after system resume

 sound/pci/hda/patch_realtek.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

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2.7.4