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authorWon Chung <wonchung@google.com>2023-07-27 20:10:25 +0000
committerFelix Held <felix-coreboot@felixheld.de>2023-08-03 12:54:31 +0000
commitbc1533e08975b285e589447f329ef25bfe585ef9 (patch)
treea620e006be9ba7a13cc1cb0c18c566d45655051f /src/mainboard/google/rex/variants
parentf232b19e56e21415f403826bf6cdb643f214e0f4 (diff)
mb/google: Add more comment on GFX devices for the future reference
Add more details to instruct future boards/models implementers regarding how GFX devices should be added. If HDMI and DP connectors are enumerated by the kernel in /sys/class/drm/ then corresponding GFX device should be added to ACPI. It is possible that some connectors do not have dedicated ports, but still enumerated. The order of GFX devices is DDIA -> DDIB -> TCPX. BUG=b:277629750 TEST=emerge-brya coreboot Change-Id: I59e82ee954a7d502e419046c1c2d7a20ea8a9224 Signed-off-by: Won Chung <wonchung@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/76776 Reviewed-by: Kapil Porwal <kapilporwal@google.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Jakub Czapiga <jacz@semihalf.com>
Diffstat (limited to 'src/mainboard/google/rex/variants')
-rw-r--r--src/mainboard/google/rex/variants/rex0/overridetree.cb5
1 files changed, 3 insertions, 2 deletions
diff --git a/src/mainboard/google/rex/variants/rex0/overridetree.cb b/src/mainboard/google/rex/variants/rex0/overridetree.cb
index 793a46d7c5..0cbea7b052 100644
--- a/src/mainboard/google/rex/variants/rex0/overridetree.cb
+++ b/src/mainboard/google/rex/variants/rex0/overridetree.cb
@@ -154,18 +154,19 @@ chip soc/intel/meteorlake
# DDIA for eDP
register "device[0].name" = ""LCD""
# DDIB for HDMI
+ # If HDMI is not enumerated in the kernel, then no GFX device should be added for DDIB
register "device[1].name" = ""DD01""
# TCP0 (DP-1) for port C0
register "device[2].name" = ""DD02""
register "device[2].use_pld" = "true"
register "device[2].pld" = "ACPI_PLD_TYPE_C(LEFT, LEFT, ACPI_PLD_GROUP(1, 1))"
- # TCP1 (DP-2) unused
+ # TCP1 (DP-2) is unused for any ports but still enumerated in the kernel, so GFX device is added for TCP1
register "device[3].name" = ""DD03""
# TCP2 (DP-3) for port C1
register "device[4].name" = ""DD04""
register "device[4].use_pld" = "true"
register "device[4].pld" = "ACPI_PLD_TYPE_C(RIGHT, LEFT, ACPI_PLD_GROUP(2, 1))"
- # TCP3 (DP-4) unused
+ # TCP3 (DP-4) is unused for any ports but still enumerated in the kernel, so GFX device is added for TCP3
register "device[5].name" = ""DD05""
device generic 0 on end
end