soc/intel/cmn/gfx: Fix GFX modeset issue with dual-display

This patch fixes the redundent GFX modeset issue when a dual display
is attached (e.g. an eDP display and an HDMI display).

The issue was caused by the MBUS joining logic not considering the
display type. This patch introduces three types of display: internal,
external, and dual-display. The MBUS joining logic is then updated
to consider the display type and ensure that the correct pipes are
joined to the MBUS:

For internal-only displays, only PIPE-A is joined to the MBUS.
For external displays, no pipes are joined to the MBUS.
For dual-displays, all available pipes are joined to the MBUS.

BUG=b:284799726
TEST=Able to fix the redundent modeset issue when eDP and HDMI attached
to the google/rex.

Change-Id: Ie2a3b9f1212a9dcab2b7305078fe22ee35e7423c
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78691
Reviewed-by: Nick Vaccaro <nvaccaro@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions