On 10.02.2018 19:57, Arthur Heymans wrote:
"Taiidan@gmx.com" Taiidan@gmx.com writes:
I would like to add this information to the wiki so I am wondering if anyone has successfully used for instance dual 8GB graphics cards with coreboot.
I don't think that this gpu memory is mapped into the linear memory space. Such a GPU will typically have a PCI memory resource BAR that is (only) 256M large (could be 512M or more these days).
I am not sure if this would be an issue due to coreboot only having 32bit MMIO space.
It depends a bit on how things are configured but with a fairly common 2G mmio space below 4G I think it is unlikely for 2 external GPU's to be an issue.
It would of course be nice to have 64bit BAR support but that would require substantial changes in the allocator and more importantly a lot of time spend in a sane and thoughtful design...
I think Myles Watson (not 100% sure) worked on an improved resource allocator with 64 bit resource support for v3. I do not know if it ever was merged in v4, or if that was instead a port of the v2 allocator to v3, in which case this would be mostly what we have now. The mails about this are mostly from 2009.
Regards, Carl-Daniel