Furquan Shaikh has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/41471 )
Change subject: soc/intel/broadwell: Mask lower 20 bits of TOLUD and TOLM in systemagent.asl ......................................................................
Patch Set 6:
(1 comment)
https://review.coreboot.org/c/coreboot/+/41471/6/src/soc/intel/broadwell/acp... File src/soc/intel/broadwell/acpi/systemagent.asl:
https://review.coreboot.org/c/coreboot/+/41471/6/src/soc/intel/broadwell/acp... PS6, Line 156: If (Local0 == Local1) {
I don't think any chipset code reserves this region.
Are you saying that it should never be the case that TOLUD == MEBA?
I don't know why we can't repurpose the ME space in this case.
Repurpose ME space for performing allocation for other devices? That wouldn't really work. Or, maybe I misunderstood your comment?
If we had exactly 4GiB memory installed. ME would cover the space directly
below 4GiB. Which includes things that are forwarded to DMI for sure, e.g. ROM and the RCBA which was often at 0xfed1c000.
In that case, that part of the DRAM would be remapped above 4G and hence ME region would still be below TOLM?
Just saw a memory map chapter in the TGL BIOS Spec, which says all the stolen
regions have to be reserved, and the list includes the ME space. That doesn't make any sense in most cases
Why is that?