Sukumar Ghorai has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/77067?usp=email )
Change subject: mb/intel/mtlrvp: Disable C1-state auto demotion for mtl-rvp ......................................................................
mb/intel/mtlrvp: Disable C1-state auto demotion for mtl-rvp
C1-state auto demotion feature allows hardware to determine C1-state as per platform policy. Since platform sets performance policy to balanced from hardware, auto demotion can be disabled without performance impact.
Also, disabling this feature results soc to enter PC2 and lower state in camera preview case and save platform power.
Note: C1 demotion heuristics used EPB parameter to balance between power and performance, i.e. low threshold when EPB is low in-order to get C1 demotion faster and vice-versa. ChromeOS operates at default EPB=0x7 (low EPB) in both AC/DC, so in DC mode it gets more C1 demotion hits than expected (similar to AC mode) and losing power respectively. ref. https://review.coreboot.org/c/coreboot/+/76827
BUG=b:286328295 TEST=Code compiles and correct value of c1-state auto demotion is passed to FSP. Also verified PC residency improvement ~10% in camera preview case.
Change-Id: I1b2db634176f0072c535608c5600846a9086fef1 Signed-off-by: Sukumar Ghorai sukumar.ghorai@intel.com --- M src/mainboard/intel/mtlrvp/variants/baseboard/mtlrvp_p/devicetree.cb 1 file changed, 3 insertions(+), 0 deletions(-)
git pull ssh://review.coreboot.org:29418/coreboot refs/changes/67/77067/1
diff --git a/src/mainboard/intel/mtlrvp/variants/baseboard/mtlrvp_p/devicetree.cb b/src/mainboard/intel/mtlrvp/variants/baseboard/mtlrvp_p/devicetree.cb index f8f61a5..17a92a8 100644 --- a/src/mainboard/intel/mtlrvp/variants/baseboard/mtlrvp_p/devicetree.cb +++ b/src/mainboard/intel/mtlrvp/variants/baseboard/mtlrvp_p/devicetree.cb @@ -52,6 +52,9 @@ # Enable S0ix register "s0ix_enable" = "1"
+ # Disable C1 C-state auto-demotion + register "disable_c1_state_auto_demotion" = "1" + # Enable energy reporting register "pch_pm_energy_report_enable" = "1"