Hi,
Sorry, I've skimmed through this thread but I think I'm missing some messages. If I'm understanding this thread right, we now have special cases for UMA and SMM memory to mark them as uncachable. But a proper subtractive mtrr scheme should handle that automatically, right? I guess what it boils down to is, is memory reserved for SMM reported as a ram resource or no? Can SMM memory be marked as uncachable or does it need to be untouched by MTRRs? Also, does the ram resource code properly handle areas that need to be reserved for ACPI, etc tables and the flash chip?
I've subtractive mtrr setup code that can handle the most basic cases, a memory of a power of 2 size <4gb minus any number of power of 2 sized areas, but I'm not sure how to work at around 4GB, and I don't have any systems that have onboard video and can handle 4GB of ram to poke at.
Thanks, Corey