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

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

On 03.08.2015 15:02, Hans de Goede wrote:
> 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
> 
You can tell, just by looking at garbled pattern, what is the actually problem!?

On Mon, Aug 3, 2015 at 9:02 AM, Hans de Goede <hdegoede at redhat.com>
wrote:
> 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.
His patches should have defaulted it to DRI 2 I think, so this is
unnecessary. In fact you should have had to say "DRI" "3" to
get DRI3
with his patches.
 --
>
> 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.
Ah yes. Very different problem indeed. I actually suspect it has to do
with swizzling. Look at the white pattern of the moon -- it's all in a
line. That means that it expected some locality and instead it got
drawn all on a line. If it were merely a stride problem, I'd expect to
see strips of the moon below and offset from one another.

So... take a look at nv30_miptree_from_handle -- I wonder if it can
now receive swizzled textures where it couldn't before.

  -ilia

Hi,

On 03-08-15 17:36, Ilia Mirkin wrote:
> On Mon, Aug 3, 2015 at 9:02 AM, Hans de Goede <hdegoede at
redhat.com> wrote:
>> 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.
>
> His patches should have defaulted it to DRI 2 I think, so this is
> unnecessary. In fact you should have had to say "DRI"
"3" to get DRI3
> with his patches.
>   --
>>
>> 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.
>
> Ah yes. Very different problem indeed. I actually suspect it has to do
> with swizzling. Look at the white pattern of the moon -- it's all in a
> line. That means that it expected some locality and instead it got
> drawn all on a line. If it were merely a stride problem, I'd expect to
> see strips of the moon below and offset from one another.
>
> So... take a look at nv30_miptree_from_handle -- I wonder if it can
> now receive swizzled textures where it couldn't before.
Ok, that does go in the direction I am expecting the problem to be,
but I'm afraid I'm going to need a bit more guidance, what exactly
am I looking for in that function / which "knobs" should I try to
vary / play with to maybe fix this ?

Regards,

Hans