Me and Alex talked to a BIOS guys yesterday exactly about that, a
dynamic way to query this info from BIOS, he just told us to reserve 32M
to cover 4K display.
On 04/06/2018 04:30 AM, Christian König wrote:
I wonder if there's no way to determine which part of VRAM is being
scanned out. If there was, we could just create a normal BO covering
that, which would get destroyed once no CRTC references it anymore.
Unfortunately it goes further than that. The stolen VRAM is needed for
VGA emulation, not only for scanout.
But yes I agree that we somehow figure that value out from the BIOS.
If I'm not completely mistaken I've also seen some atombios table with
that info in some discussion.
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