Re: [PATCH 3/4] drm/i915: Allow userspace to hint that the relocations were known

[Chris Wilson <chris@chris-wilson.co.uk>]

On Sat, 10 Nov 2012 18:16:16 +0100, Daniel Vetter <daniel@ffwll.ch> wrote:
> - Can we abolish the pending_read/write_domains and just go with a
>   per-object GPU_WRITE flag? Afaik that's all we need with the
>   flushing_list gone. To avoid a massive rewrite of the code I'm thinking
>   of just keeping around a pending_gpu_write bool (since reads are
>   implicit) and then using that to fill out generic gpu domains in
>   i915_gem_execbuffer_move_to_active. E.g. set all gpu read domains if
>   there is no write, otherwise just set the render domain in both.

Just a quick comment. I started with just a WRITE flag, then realised I
needed to mark the read domains as well (for GPU activity tracking). So
I concluded that just passing along the domains was easy enough for
userspace and better for future-proofing. That is definitely one of the
places where we need to be careful with designing the API - more ideas
are welcome.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre