SH Kim has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/35533 )
Change subject: mb/google/hatch: Support separate fixed PL1 setting for tablet mode ......................................................................
Patch Set 1:
(1 comment)
https://review.coreboot.org/c/coreboot/+/35533/1//COMMIT_MSG Commit Message:
https://review.coreboot.org/c/coreboot/+/35533/1//COMMIT_MSG@10 PS1, Line 10: but DPTF passive policy 1.0 cannot support it.
Is it okay to just change the PL1 setting in ASL without DPTF really knowing about it? What is the i […]
We don't have bug for this implementation. DPTF uses MSR PL1 only and system takes the lowest value of MSR PL1 and MMIO PL1, so there will be 3 case in tablet mode. @Sumeet, Kane, can you confirm about this implementation?
Case1: mmio_pl1 > DPTF PL1 max - No impact on DPTF operation (MSR PL1 activated)
Case2: DPTF PL1 max > mmio_pl1 > DPTF PL1 min - In lower temperature, DPTF wants to set higher PL1 value than mmio_pl1 => PL1 is limited to mmio_pl1 (MMIO PL1 activated) - In higher temperature, DPTF wants to set lower PL1 value than mmio_pl1 => PL1 is set by DPTF (MSR PL1 activated)
Case3: mmio_pl1 < DPTF PL1 min - DPTF always wants to set higher PL1 value than mmio_pl1 => PL1 is limited to mmio_pl1, so system works like it has fixed PL1 value