sof-audio-pci doesn't work under discrete-only mode

[khfeng]

Describe the bug
After disable Intel GFX in the BIOS, sof-audio-pci doesn't work anymore under discrete-only mode.

To Reproduce
1.Disable Intel GFX, system is in Nvidia only mode.
2.Lose both audio input/output.

Reproduce rate
100%

Expected result
Audio keeps working under discrete-only mode.

Actual result
For both linux-next and sof-dev:
[ 14.025657] sof-audio-pci 0000:00:1f.3: ASoC: can't set iDisp3 Pin hw params: -22
[ 14.026189] sof-audio-pci 0000:00:1f.3: ASoC: DAI prepare error: -22
[ 14.026192] iDisp3: ASoC: backend prepare failed -22

There's a NULL kernel dereference in sof-dev nonetheless.
Test recipe
Kernel:https://github.com/thesofproject/linux/commits/topic/sof-dev commit: 7136b5a
FW: SoF 1.4.2
Tplg: From SoF 1.4.2
Platform:CML-H Laptop with ALC285

dmesg-sof-dev.txt
dmesg-next.txt

[plbossart]

@kv2019i can you look at the kernel ooops? even if this looks like a missing Kconfig option I don't recall seeing an oops before.

@khfeng we are aware of a problem leading to a system hang, firmware 1.4.2 is missing an important fix unfortunately see thesofproject/sof#2806

[khfeng]

The system doesn't hang.

Is it possible to release signed 1.5-rc* firmware so I can test it?

[plbossart]

@lgirdwood what's the ETA for 1.5? we are at -rc3, so should be coming right up, yes?

[kv2019i]

@khfeng Can you post alsa-info.sh output from this system?

You may also need to update alsa-ucm package. Only git master currently has fixes needed for these laptops where HDMI/DP of the integrated graphics is disabled. See my comment at #1985 (comment)

This doesn't help with the oops, but will be needed in the end as well.

[khfeng]

Yes the latest UCM files help. Let's close this issue.
The oops is a different issue though.