Furquan Shaikh has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/41155 )
Change subject: soc/intel/common/block/systemagent: Use TOUUD as base for MMIO above 4G ......................................................................
Patch Set 2:
(1 comment)
https://review.coreboot.org/c/coreboot/+/41155/2/src/soc/intel/common/block/... File src/soc/intel/common/block/systemagent/systemagent.c:
https://review.coreboot.org/c/coreboot/+/41155/2/src/soc/intel/common/block/... PS2, Line 118: if (!get_enable_above_4GB_mmio())
And causing such issue when Above 4GB base and limit size is incorrect.
What were the MMIO addresses that were advertised in ACPI tables before and after your change? Do you have dumps of the tables?
After making sure we have right base and limit like below CL, we don't see such issue as mentioned above.
If there was an error in reporting and now it is fixed, why not always advertise the correct MMIO window available above 4G? Why is it made conditional?
Also i could see an FSP UPD which does some additional programming if we like to enable memory above 4GB.
That seems to be used only for ACPI table generation. I didn't really see any different programming happening with that UPD?