[Bug 1899586] Re: Fix broken MSI interrupt after HDA controller was suspended

** Tags added: oem-priority originate-from-1896576 somerville

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https://bugs.launchpad.net/bugs/1899586

Title:
Fix broken MSI interrupt after HDA controller was suspended

Status in HWE Next:
New
Status in linux package in Ubuntu:
Confirmed
Status in linux-oem-5.6 package in Ubuntu:
Invalid
Status in linux source package in Focal:
Confirmed
Status in linux-oem-5.6 source package in Focal:
Confirmed
Status in linux source package in Groovy:
Confirmed
Status in linux-oem-5.6 source package in Groovy:
Invalid

Bug description:
[Impact]
After HDA controller gets suspended and resumed, no MSI interrupt raised
when plugging headset to the audio jack.

[Fix]
Power up the Realtek codec when HDA controller runtime resumes.

[Test]
1) Make sure both codec and HDA controller are runtime suspended.
2) Runtime resume the HDA controller without runtime resume the codec.
3) Plug a headset and see if the system can detect anything.

With the fix applied, we can see azx_interrupt() is working again by
using ftrace.

[Regression Potential]
If there's any system that is not affected by this issue, runtime-resume
the HDA controller will take a slightly longer time. It's rather
unlikely, since _all_ systems with Realtek codec we tested have this
issue, regardless of AMD or Intel.

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