[Intel-gfx] [PATCH] drm/i915: Report context GTT size

[Chris Wilson]

On Fri, Oct 16, 2015 at 05:34:55PM +0100, Tvrtko Ursulin wrote:
> I have a slight unknown relating to how long would this ABI be
> useful. If things are moving towards SVM, and the fact pre-gen8
> platforms can already use get_aperture, would that make it a bit
> short lived?

Optimist. It is certainly a better fit than the cascade of get param and
hardcoded sizes based on gen (which ignore differences between kernels)
which a fallback to get_aperture. Now although I can't just drop the old
code (because I need to support kernels without this interface), it does
make that code simpler and more robust against any future change.
 
> And get_aperture would even be a better place for this if PPGTT size
> will always be the same for all clients.

Hmm, I'm regretting my earlier push for extending get_aperture.
Constants like this would be better off in GET_PARAM (or
CONTEXT_PER_PARAM as applicable), and only using get_aperture where we
want the side-effect of scanning for available space (e.g. the extra
stolen information would be more useful in get_aperture as we there do
want to know the largest object we can allocate given current usage, but
we may also want to stick the total amount of stolen in a param for
convenience).

[snip]
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre