Nouveau - Jul 2015 - "enable dri3 support without glamor" causes gnome-shell regression on nv4x

Hi Maarten,

xf86-video-nouveau causes a garbled display when running
gnome-shell on nv4x (tested with nv43 and nv46) since this commit:

http://cgit.freedesktop.org/nouveau/xf86-video-nouveau/commit/?id=241e7289f25a342a457952b9b0e539c2f0b81d99

I've seen some discussion about issues caused by enabling dri,
but AFAIK no solution let.

I have time to help with debugging / fixing this, but I will
need some guidance where to start as I'm still learning
the ropes wrt nouveau.

Regards,

Hans

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.

Note that I'm going to land Mario's patch today to disable DRI3 by
default when using EXA.

  -ilia

On Thu, Jul 30, 2015 at 9:16 AM, Hans de Goede <hdegoede at redhat.com>
wrote:
> Hi Maarten,
>
> xf86-video-nouveau causes a garbled display when running
> gnome-shell on nv4x (tested with nv43 and nv46) since this commit:
>
>
http://cgit.freedesktop.org/nouveau/xf86-video-nouveau/commit/?id=241e7289f25a342a457952b9b0e539c2f0b81d99
>
> I've seen some discussion about issues caused by enabling dri,
> but AFAIK no solution let.
>
> I have time to help with debugging / fixing this, but I will
> need some guidance where to start as I'm still learning
> the ropes wrt nouveau.
>
> Regards,
>
> Hans
> _______________________________________________
> Nouveau mailing list
> Nouveau at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/nouveau

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