Paul wrote…
What board is this and what chipset?
It is a custom laptop platform where we have been tasked to replace the stock AMI BIOS with coreboot. It uses Intel Comet Lake.
Sorry, I do not know the exact answer, but looking at the quirk implementation in Linux 5.10-rc5, it consists actually of two quirks (also `ALC256_FIXUP_ASUS_HEADSET_MODE`), if `.chain_id` does what I think [1][2].
At you should be able to copy the pin values, the quirk sets. No idea, if that is all.
I’ve been staring at that code in the kernel all day trying to figure out what changes it makes along with Intel’s High Definition Audio Specification document and the ALC256 datasheet.
As this is a commercial undertaking, I recommend you contract support from the companies working on coreboot [3].
At some point in the future, probably when this project is finished and I have submitted some patches, then I am hoping to email Martin to get us added to that list.
-Andy.