Benjamin Doron has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/38978 )
Change subject: [WIP] mb/acer: Add Acer Aspire ES1-572 ......................................................................
Patch Set 7:
(1 comment)
https://review.coreboot.org/c/coreboot/+/38978/5/src/mainboard/acer/es1-572/... File src/mainboard/acer/es1-572/devicetree.cb:
https://review.coreboot.org/c/coreboot/+/38978/5/src/mainboard/acer/es1-572/... PS5, Line 223: register "SendVrMbxCmd" = "2"
I never verified that it was required in the first place. […]
I haven't seen any information on it either. Perhaps the EDS mentions it, or maybe the full datasheet for the relevant VR. I have neither.
I did, however, notice that the Skylake FSP goes gold at version 2.0.0.0 with this UPD present. The vendor firmware for my board, using the 1.9.0.0 reference code, does not mention it all in the advanced settings. It's possible that the vendor firmware does not allow the setting to be changed and configures it directly (like the HSIO UPDs), but I would find this unlikely. The rest of the power settings are configurable.
So, maybe we can sometimes extrapolate from version information, etc?