KMS and TTM questions

Dave Airlie airlied at
Mon Oct 3 12:27:40 PDT 2011

On Mon, Oct 3, 2011 at 8:14 PM, Alan Cox <alan at> wrote:
>> the front buffer. The problem was the buffer offset for the second
>> allocation was the same as the VQ buffer. I'm stump to what I'm doing
>> wrong, so does anyone have a idea?
> I gave up trying to understand TTM (they don't make happy pills that big)
> and used GEM and a simple allocator. The private allocator GEM change
> means you can now use GEM to magic up objects that are in on card or
> stolen memory where applicable not just backed in system memory.

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
should also state the limitations your advice leads to.

For a VIA device I think  TTM is necessary as they preallocate large
piece of RAM to VRAM area like 128MB or so and you need to migrate
objects in/out of that area to use it.


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