[Intel-gfx] [PATCH v2, 2/4] drm/i915: simplify testing for the global default context

[Dave Gordon]

On 05/01/16 10:06, Chris Wilson wrote:
> On Mon, Jan 04, 2016 at 01:38:26PM -0800, Jesse Barnes wrote:
>> On 01/04/2016 11:39 AM, Chris Wilson wrote:
>>> This series is NAKed.
>>
>> Why?  Because you want things in a different order?  Or do you object to something in Dave's reply?
>
> The series was intended as a code cleanup and in the process tried to
> introduce a false concept that I objected to. Since the cleanup was not
> predicated upon that idea, the patches would have been much tidier
> without it.

I don't think it's a false concept; there very evidently *IS* a global 
default context, so why not flag it as such by name, rather than by 
implication. and the subsequent cleanup *does* require it.

> The fundamental issue at stake here is execlists behaves badly and we
> have to futz around in higher level code to undo that mistake.
> -Chris

Now I agree that the execlist->default_context is a bad idea, and that's 
exactly what we will get rid of in patch 4, but we can't do it until 
these precursor patches have separated the various purposes for which it 
is used into distinct categories, each of which is then replaced by a 
cleaner alternative.

So it *is* a step towards rewriting execlists, even if it doesn't (at 
this stage) fix everything you might eventually want.

.Dave.