[REGRESSION] "ALSA: HDA: Early Forbid of runtime PM" broke my laptop's internal audio

[Michael Catanzaro]

Hi,

On my System76 Gazelle Pro (gazp9) laptop, internal audio broke after 
upgrading to kernel 5.10.

The laptop's speakers produce no sound. Audio from headphones still 
works fine. A quick test is to visit GNOME System Settings -> Sound -> 
Output, select Test, click Front Left or Front Right and notice there 
is no sound. I tested a mainline kernel revision from yesterday 
(5.11-rc5+) and the regression is not yet fixed. I bisected the 
regression to "ALSA: HDA: Early Forbid of runtime PM":

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a0645daf16101bb9a6d87598c17e9a8b7bd60ea7

I created a downstream bug report here, including some bits from dmesg 
that may or may not be relevant in comment #2:

https://bugzilla.redhat.com/show_bug.cgi?id=1918933

Audio devices:

$ lspci | grep -i audio
00:03.0 Audio device: Intel Corporation Xeon E3-1200 v3/4th Gen Core 
Processor HD Audio Controller (rev 06)
00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset 
High Definition Audio Controller (rev 05)

OS: Fedora 33

I'm happy to provide any additional required info or test patches if 
you CC me, since I'm not a kernel developer and am not subscribed to 
these lists. Thanks.