tree 50ba949a0d7382dc30aff8b85d992033e6413825
parent 787b2b44afb94d60b17daea16fc9fa6d364c9c5c
author Leah Rowe <info@minifree.org> 1708695211 +0000
committer Felix Held <felix-coreboot@felixheld.de> 1709565741 +0000

nb/haswell: Disable iGPU when dGPU is used

This is usually is handled by Haswell mrc.bin, disabling VGA
decode on the iGPU when a dGPU is installed. However, Broadwell
mrc.bin does not, so the iGPU and dGPU are both enabled.

This patch disables legacy VGA cycles for iGPU, under such
conditions. It has been tested on Broadwell mrc.bin when
using a graphics card on Dell OptiPlex 9020 SFF (currently
under review at this time of writing, submitted by Mate
Kukri).

This patch has also been tested when Haswell mrc.bin is used,
and there are seemingly no breaking changes caused by it.

Change-Id: I1df0a3aa42f8475b7741007bf3e28c2e089d916b
Signed-off-by: Leah Rowe <info@minifree.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80717
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>