Michael Niewöhner 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 9:
(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 don't think, there is any reason to show it as advanced setting in vendor fw, if that is for fixin […]
What I could find out: There are issues with (some) IMVP8 controllers.
IslVrCmd: "specific VRs [...] require tunings before sending SETVID command to '0V'" "0 - No VR command sent" "1 - A VR mailbox command is sent for IA and GT rails only." (type=pcode, cmd=0x80000012, data=0) "2 - A VR mailbox command is sent for IA, GT, and SA rails." (type=pcode, cmd=0x80000012, data=1) see CB:22763
The "specific VRs" are at least ISL9585X/ISL9586X.
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SendVrMbxCmd (deprecated in KBL): "VR specific mailbox commands." "0 - No VR command sent." "01b - A VR mailbox command specifically for the MPS IMPV8 VR will be sent." (workaround to enter PS4, type=pcode, cmd=0x80000E18, data=1) "10b - VR specific command sent for PS4 exit issue." (type=pcode, cmd=0x80000034, data=0) "11b - send both" bitwise encoding
SendVrMbxCmd1 (only in KBL): "VR specific mailbox commands." "000b - no VR specific command sent." "001b - A VR mailbox command specifically for the MPS IMPV8 VR will be sent." (workaround to enter PS4, type=pcode, cmd=0x80000E18, data=1) "010b - VR specific command sent for PS4 exit issue." (type=pcode, cmd=0x80000034, data=0) "100b - VR specific command sent for MPS VR decay issue." (type=pcode, cmd=0x80000038, data=1) bitwise encoding
According to CB:18200 the PS4 exit issue applies to MP2939 (IMVP8) but not MPS2949 (IMVP9/8).