Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/32928 )
Change subject: mb/{i945}: Drop CHANNEL_XOR_RANDOMIZATION selection ......................................................................
Patch Set 2:
(2 comments)
There's this specification update for the 915 chipset series that details stuff about Channel XOR Randomization:
https://www.portwell.com.tw/download/ec/datasheet/Mobile%20Intel_915GM_Updat...
It's not the same chipset, but the bit definitions seem to make sense. Please take the comments below with a pinch of salt, as there might be differences.
https://review.coreboot.org/#/c/32928/2/src/northbridge/intel/i945/raminit.c File src/northbridge/intel/i945/raminit.c:
https://review.coreboot.org/#/c/32928/2/src/northbridge/intel/i945/raminit.c... PS2, Line 2116: This enables XOR randomization (bit=0), but on the other side of the "else" side there's nothing to disable it (bit=1). Maybe it's missing?
https://review.coreboot.org/#/c/32928/2/src/northbridge/intel/i945/raminit.c... PS2, Line 2117: This selects the host address bit (0 = bit 11, 1 = bit 17) to XOR with the Channel Select bit, if XOR randomization is enabled.
Does it make sense to set this bit on the "else" path, when XOR randomization is disabled?