On 06.06.2016 23:40, Kyösti Mälkki wrote:
On Mon, Jun 6, 2016 at 10:36 PM, ron minnich firstname.lastname@example.org wrote:
I'm getting the sense here that reasonably modern CPUs can easily handle the 2G hole. From what I've seen, it would not cause trouble for older CPUs because they're most likely to be in small systems that are not likely to have more than 2G memory anyway (I'm thinking of the vortex).
Not that I would particularly care, but was i945 able to reclaim memory from below 4GiB to above 4GiB? There used to be a fair amount of Lenovo T60/X60(s) users.
I don't think we should use the 2GiB limit for all x86 platforms. It's more a question for those platforms that are actively maintained and at least support PAE, IMO.
Regarding i945, I had a look at the code and there is a TOM register that's programmed to the total amount of DRAM. But sadly it's undocu- mented (at my level of NDA) and coreboot doesn't seem to advertise memory above 4GiB (I haven't tried it yet though).