Attention is currently required from: Tim Crawford. Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/57835 )
Change subject: mb/system76: tgl-u: Add gfx register for GMA ACPI ......................................................................
Patch Set 1:
(1 comment)
File src/mainboard/system76/darp7/devicetree.cb:
https://review.coreboot.org/c/coreboot/+/57835/comment/f0059fe2_a267393c PS1, Line 110: GMA_STATIC_DISPLAYS This is a short form for some legacy copy-pasta that we couldn't remove without risking regressions. If you just need backlight controls to work, GMA_DEFAULT_PANEL(0) is preferred.
The numbers are explained in an appendix of the ACPI spec. Intel's pre- ferred way to handle it is to let the OS driver know about available ports via VBT, and query the info via the IGD OpRegion at runtime. A bit overkill because there doesn't seem to be an OS that really cares about a correct implementation, hence we only implemented the static numbers.