[Intel-gfx] [RFC PATCH 00/11] i915 HW context support

[Ben Widawsky]

On Tue, 14 Feb 2012 18:17:57 -0500
Adam Jackson <ajax at redhat.com> wrote:

> On 2/14/12 4:09 PM, Ben Widawsky wrote:
> 
> > The IOCTLs defined here may also be used with ppgtt (real ppgtt) but the
> > interface may be insufficient for that. The contexts do provide a
> >
> 
> A... what?

This was left up to the reader as I forgot what I meant to say..

> 
> Series looks reasonable to me.  The one thing that makes me nervous is 
> 4/11 mentioning the BIOS, which honestly seems like an insane thing to 
> let your BIOS have _any_ say in, but then Intel sure does like to give 
> the BIOS a chance to make the OS less functional.  The code in 7/11 
> effectively limits things to between 4k and 1M; does that actually make 
> sense?  I can't imagine wanting to allocate only 4k if it turns out we'd 
> always need at least (say) 32k.
> 

At least up to Gen6, 4k was sufficient. It begins to grow exponentially
afaict after that, and I've not tested on enough platforms to find out
if BIOS does any weird shit... all I know is that it can. I'll see if I
can't make this look more sane.

> I have admittedly not read any of the docs on how this is meant to work, 
> apologies if that'd answer this.
> 
> - ajax

Nah, you're good. Thanks.

Ben