soc/intel/{adl, mtl}: Avoid redundant display init by joining to MBUS
This patch ensures that the IGD joins the MBUS when the firmware splash
screen feature is enabled (aka BMP_LOGO config is enabled).
For ChromeOS platform, it prevents the i915 driver from reinitializing
the display, which can save up to 75ms-80ms of boot time and eliminate
a brief period of blank screen between the firmware splash screen and
the OS login prompt.
BUG=b:284799726
TEST=Able to build and boot google/rex.
Change-Id: I36af167afa902053a987602d494a8830ad9b1b1a
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78387
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>
Reviewed-by: Nick Vaccaro <nvaccaro@google.com>
diff --git a/src/soc/intel/alderlake/Kconfig b/src/soc/intel/alderlake/Kconfig
index 1002f5a..d70526b 100644
--- a/src/soc/intel/alderlake/Kconfig
+++ b/src/soc/intel/alderlake/Kconfig
@@ -82,6 +82,7 @@
select SOC_INTEL_COMMON_RESET
select SOC_INTEL_CSE_SEND_EOP_LATE if !BOARD_GOOGLE_BRYA_COMMON
select SOC_INTEL_CSE_SET_EOP
+ select SOC_INTEL_GFX_MBUS_JOIN if MAINBOARD_HAS_CHROMEOS && BMP_LOGO
select SOC_INTEL_MEM_MAPPED_PM_CONFIGURATION
select HAVE_INTEL_COMPLIANCE_TEST_MODE
select SSE2