KMS and TTM questions

James Simmons jsimmons at
Tue Oct 4 07:08:37 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.

I did both as I like my cake and to eat it too :-)

> 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.

The accelerated moves is what made me implement an TTM layer. I 
wanted to try out using ttm_bo_move for the fbcon copyarea and 
imageblit functions as a experiment. Also in the future I like
totry out tiling support for fbcon with my dri driver. Yes fbcon 
supports tiles. All thats down the road. For now I just need to get a 
working driver.

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