I notice that the fixed MTRR for region 0xd0000 is defined as ROM. The type is WRPROT, value 5. Does this mean cacheable? Still worse, if it is write protected, why did DoC code even work ... After all, 0xd0000 should not be writeable! I put a scope on the we# pin on the DoC and it is clearly being written, once for each command to DoC. I don't think the MTRR is disabling writes ...
Shouldn't all the MTRRs above 0xa0000 be UNCACHABLE up to 0xf0000, which is ROM? The debug prints from linuxbios indicate that fixed MTRR is enabled. This is very strange. ron
