[coreboot-gerrit] Change in coreboot[master]: soc/intel/tigerlake: Disable C1 Cstate Demotion

[Ravishankar Sarawadi (Code Review)]

Ravishankar Sarawadi has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/46438 )

Change subject: soc/intel/tigerlake: Disable C1 Cstate Demotion
......................................................................

soc/intel/tigerlake: Disable C1 Cstate Demotion

Disable C1 state auto demotion to improve SoC power.

When set, processor will conditionally demote C3/C6/C7 requests
to C1 based on uncore auto-demote information.

BUG=b:161215906
TEST=Measure and confirm power usage reduction for key use cases
 eg 'Google Meets video call'
Signed-off-by: Ravi Sarawadi 
Signed-off-by: Shweta Malik 
Change-Id: I649cafbaf03917d76521aa5f76ec58d218e1a1b1
---
M src/soc/intel/tigerlake/fsp_params.c
1 file changed, 4 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/38/46438/1

diff --git a/src/soc/intel/tigerlake/fsp_params.c b/src/soc/intel/tigerlake/fsp_params.c
index 38f444b..f9f17f8 100644
--- a/src/soc/intel/tigerlake/fsp_params.c
+++ b/src/soc/intel/tigerlake/fsp_params.c
@@ -357,6 +357,10 @@

/* EnableMultiPhaseSiliconInit for running MultiPhaseSiInit */
    params->EnableMultiPhaseSiliconInit = 1;
+
+	/* Disable C1 Cstate Demotion */
+	params->C1StateAutoDemotion = 0;
+
    mainboard_silicon_init_params(params);
 }