[Nouveau] Should I expect nouveau on 4.6 to work on a GM206?

[Ilia Mirkin]

On Sun, Jun 26, 2016 at 2:04 PM, Andy Lutomirski <luto at amacapital.net> wrote:
> Eeek!  My desire to hack on EXA is pretty low.  If there was some

Well, the EXA hacking was all done a long time ago. You'd just need to
add support for sticking 4 vertices into a buffer. (Maxwell killed
direct vertex submit, which was incredibly convenient for the DDX.)

> straightforward way I could try to figure out why GLAMOR was so slow,
> maybe I could fiddle with that a bit.

Upgrade mesa & pray. I think that X11 can end up being pretty
glReadPixels-heavy, which in a UMA system is ~free, but much more
expensive when the FB is in VRAM. Recently some changes were committed
to cache the entire texture in a staging texture if someone does a lot
of readpixels on it. Could help. Or could be totally unrelated.

You could do an apitrace of the X server
(github.com/apitrace/apitrace) and then analyze what all it's doing.

>
> FWIW, my i915-based laptop uses the modesetting driver and GLAMOR as
> well, and it's plenty fast, so I don't think the problem is that
> GLAMOR is inherently terrible at legacy X11 operations.

Different workloads, I suppose. I had to use GLAMOR on a SKL while the
regular ddx was still lacking support for it, and my favorite
screensaver was unbearably slow on it (xlock -mode wator, in case
you're curious). [And regular usage was also not great, but not to the
point of frustration.] It runs plenty fast with the SNA backend
though.

  -ilia