[Nouveau] "enable dri3 support without glamor" causes gnome-shell regression on nv4x

[Hans de Goede]

Hi,

On 30-07-15 16:09, Ilia Mirkin wrote:
> FWIW this is a fail on nv50+ as well. See for example
> https://bugs.freedesktop.org/show_bug.cgi?id=91445
>
> My suspicion is that this is due to the lack of PUSH_KICK in the *Done
> exa handlers -- works fine with DRI2, but DRI3 has no synchronization
> and so the commands never get flushed out. Easily verified by sticking
> PUSH_KICK's everywhere.

I do not believe that that is the problem, in my case it clearly
seems to be a pitch / swizzle problem rather then a synchronizarion
problem, here is what my desktop with gnome shell looks like when
using DRI2:

https://fedorapeople.org/~jwrdegoede/nv46-gnome-shell-good.jpg

And this is what it looks like when using DRI3:

https://fedorapeople.org/~jwrdegoede/nv46-gnome-shell-bad.jpg

The DRI2 screenshot is made with Mario's 2 patches on top of
current master:

http://lists.freedesktop.org/archives/nouveau/2015-July/021740.html
http://lists.freedesktop.org/archives/nouveau/2015-July/021741.html

And then adding Option "DRI" "2" to xorg.conf.

I've also tried disabling EXA using Option "AccelMethod" "none",
but that seems to also automatically disable all DRI, leading to
software rendering.

I discussed this with Ben this morning and he suggested that this
is likely a Mesa issue since with DRI3 mesa rather then the ddx
allocs the surfaces. I've tried disabling swizzling in the
mesa code by forcing nv30_miptree_create() to always take
the code path for linear textures, but that leads to the exact
same result as before that change.

Regards,

Hans