Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/43616 )
Change subject: soc/intel/cannonlake: Add i915_gpu_controller_info ......................................................................
Patch Set 1:
(3 comments)
https://review.coreboot.org/c/coreboot/+/43616/1//COMMIT_MSG Commit Message:
https://review.coreboot.org/c/coreboot/+/43616/1//COMMIT_MSG@11 PS1, Line 11: I believe : gfx.asl should be removed, but would like to hear alternatives. It seems empty (the _ADR only has meaning if there is something more associated with the device node). I would remove it.
https://review.coreboot.org/c/coreboot/+/43616/1//COMMIT_MSG@14 PS1, Line 14: Tested on system76/lemp9 - ACPI backlight control was verified. Alas, there are many paths to test. The most common one with modern Linux distributions is that ACPI only receives an event and then calls the i915 driver via IGD OpRegion to actually change the brightness. If there is no graphics driver loaded (yet), the ASL code writes registers directly and these registers have to be configured as they differ from chip to chip, see `INTEL_GMA_BCL*` in `src/drivers/intel/gma/Kconfig`.
https://review.coreboot.org/c/coreboot/+/43616/1/src/soc/intel/cannonlake/ch... File src/soc/intel/cannonlake/chip.h:
https://review.coreboot.org/c/coreboot/+/43616/1/src/soc/intel/cannonlake/ch... PS1, Line 483: backlight control It's mostly about the available display ports and only indirectly related to backlight controls (i.e. when an internal panel is advertised to the OS).