BIOS Feature Request: Add ability to specify UMA size on AMD APUs

[Mario_Limonciello]

@Wrybill_Plover

n alternative to this would be exposing the carveout size selection as a kernel parameter to amdgpu, and have that value passed on to the firmware, effectively overriding the selection in BIOS. Such an approach would be much better overall, as it would remove the dependency on specific BIOS implementation, and benefit more AMD APU-based systems. I’m not sure if that’s a viable path, however. Maybe @Mario_Limonciello , or somebody else from AMD could comment

VRAM size must be specified by the BIOS. The kernel can artificially limit it if necessary (see amdgpu.vramlimit and amdgpu.visvramlimit) but can’t make it any bigger.