[Nouveau] RFC: drop glamor from nouveau ddx

[Ben Skeggs]

On 8 July 2015 at 07:09, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Tue, Jul 7, 2015 at 5:05 PM, Ben Skeggs <skeggsb at gmail.com> wrote:
>> On 8 July 2015 at 06:06, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>> Ben,
>>>
>>> Looks like the reality is that glamor is just not hooked up properly
>>> in the nouveau DDX. Mainly it's missing DRI2, which in turn means no
>>> core GL contexts, and probably lots of other issues. While this could
>>> probably be fixed somehow, I doubt there's any advantage to using the
>>> nouveau DDX over something like modesetting nowadays.
>>>
>>> How would you feel about dropping glamor support from the nouveau ddx
>>> and failing to load for GPUs that don't have EXA support (unless
>>> AccelMode = none is forced for them). That way it'll fall back to
>>> loading modesetting which should be properly set up for DRI2 and so
>>> on.
>> I have no objections to this.  In fact, in Fedora at least (I floated
>> the idea in #nouveau a while back too), in the near future I plan on
>> having the DDX fail to load on all GPUs where modesetting+glamor can
>> be used (unless overridden by a config option).
>
> IMHO that's a little strong (I assume you mean nv50+ here?). In fact
> I'm planning to complete my Maxwell EXA impl. The current reality is
> that modesetting+glamor doesn't render correctly at least on maxwell,
> but possibly others as well. The EXA paths are very well tested and
> are stable. I think not relying on mesa in the DDX is a nice advantage
> too.
The reality is that this is what people will be using when the big
switch to wayland by default happens, and the idea is to limit the
number of codepaths we have to care about and maintain.  I'm aware
that there are a few rendering issues left in glamor (I'm not sure if
it's glamor, or our 3D driver having some bugs), but we should
probably just fix those :)

I believe Dave plans on doing something similar in Intel/Radeon too.

Ben.

>
>   -ilia