KMS and TTM questions

[Alan Cox]

> Thats fine as long as you don't want to do acceleration or object
> migration between GTT
> and VRAM type memory. Now I expect when you give out this advice you

Yes but the VIA doesn't if I recall correctly have any 'VRAM type memory'.
It's all effectively in the GART with the 'stolen' pages preloaded into
the translation tables by the BIOS at vga init time.

It has fake VRAM type memory but thats really an illusion (although one
the driver seems to like to keep up). The GEM changes do mean you can
plug the existing allocator in the VIA driver into GEM directly. Whether
that would be a good idea or not given the other things you then need to
do I don't know - but it does seem to be me to be a stepping stone in the
right direction that is much easier to make ?

I'm fairly sure the real problem is that we have no way to treat stolen
pages as generic kernel memory. The ideal case would be to simply put
that memory back into the kernel memory pools. I did a little poking at
this but it makes suspend/resume horribly exciting and while some
hardware puts it at civilised bus addresses (end of 'real' memory
usually) not everyone seems to do it that way.

You can migrate the physical pages under a GEM object as well - in fact
it happens every time pages get swapped out and back in.