tree 211d4acf4f854600cbbb18476153b6e70a6535f6
parent e811dcfd2df3d8de94c15b1ab3d04166a0647358
author Subrata Banik <subratabanik@google.com> 1693596234 +0530
committer Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> 1693672855 +0000

UPSTREAM: soc/intel/meteorlake: Fix black screen after booting to OS

This patch ensures that the VR configuration for IA, SA, and GFX is
properly initialized, assigning zero values to VR causes a black screen
(no display) issue.

Problem Statement:
Override CEP (Current Excursion Protection) value with zero aka set to
disable results into black screen issue (no display).

Solution:
Keep CEP default enabled and don't override w/ zero value.

w/o this patch:
[SPEW ]   CPU_POWER_MGMT_VR_CONFIG : CepEnable[0] : 0x0
[SPEW ]   CPU_POWER_MGMT_VR_CONFIG : CepEnable[1] : 0x0
[SPEW ]   CPU_POWER_MGMT_VR_CONFIG : CepEnable[2] : 0x0

w/ this patch:
[SPEW ]   CPU_POWER_MGMT_VR_CONFIG : CepEnable[0] : 0x1
[SPEW ]   CPU_POWER_MGMT_VR_CONFIG : CepEnable[1] : 0x1
[SPEW ]   CPU_POWER_MGMT_VR_CONFIG : CepEnable[2] : 0x1

(cherry picked from commit 96f7bd13180f284ae0dd700f3bd73a6b61139846)

Original-Change-Id: I8908e8b6c995390b559212d456db6ddf984448a3
Original-Signed-off-by: Subrata Banik <subratabanik@google.com>
Original-Reviewed-on: https://review.coreboot.org/c/coreboot/+/77611
Original-Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Original-Reviewed-by: Eran Mitrani <mitrani@google.com>
Original-Reviewed-by: Nick Vaccaro <nvaccaro@google.com>
GitOrigin-RevId: 96f7bd13180f284ae0dd700f3bd73a6b61139846
Change-Id: I778b584a0093a1648202f2c9b67b0bd85118d8f9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/coreboot/+/4836669
Reviewed-by: Subrata Banik <subratabanik@chromium.org>
Commit-Queue: Subrata Banik <subratabanik@chromium.org>
Tested-by: Subrata Banik <subratabanik@chromium.org>