Nouveau - Dec 2015 - [Bug 93300] New: Two Worlds 2 renders water incorrectly

https://bugs.freedesktop.org/show_bug.cgi?id=93300

            Bug ID: 93300
           Summary: Two Worlds 2 renders water incorrectly
           Product: Mesa
           Version: git
          Hardware: Other
                OS: All
            Status: NEW
          Keywords: regression
          Severity: normal
          Priority: medium
         Component: Drivers/DRI/nouveau
          Assignee: nouveau at lists.freedesktop.org
          Reporter: gyebro69 at gmail.com
        QA Contact: nouveau at lists.freedesktop.org
                CC: imirkin at alum.mit.edu

Created attachment 120416
  --> https://bugs.freedesktop.org/attachment.cgi?id=120416&action=edit
screenshot

In Two Worlds 2 (running in Wine 1.8-rc3) water is not rendered properly: it
looks as if textures are "split up" into several pieces, as it can be
seen in
the attached screenshot.
The problem doesn't occur with the software renderer
(LIBGL_ALWAYS_SOFTWARE=1).
Disabling optimizations doesn't help (NV50_PROG_OPTIMIZE=0).

According to my testing the problem was introduced by

commit abd326e81b06f58797be94bd655ee06b17a34f0c
Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Fri Dec 4 15:21:11 2015 -0500

    nv50/ir: propagate indirect loads into instructions

    This way $r1 = $r0 + 4; c1[$r1] becomes c1[$r0+4].

    On SM35:

    total instructions in shared programs : 6206257 -> 6185058 (-0.34%)
    total gprs used in shared programs    : 911045 -> 910722 (-0.04%)
    total local used in shared programs   : 39072 -> 39072 (0.00%)

                    local        gpr       inst      bytes
        helped           0         417        4195        4195
          hurt           0         280           0           0


Reverting the commit on current Mesa git resolves the problem here.

Apitrace log (uncompressed 150 MB):
https://drive.google.com/open?id=0B-tTbLKBl-tOQ0xNMFJlSS00S1E
The trace replays correctly on Nvidia binary drivers 340.96.

Fedora 23 32-bit
Kernel 4.4.0-rc4
X Server 1.18.0
OpenGL vendor string: nouveau
OpenGL renderer string: Gallium 0.4 on NV92
OpenGL core profile version string: 3.3 (Core Profile) Mesa 11.2.0-devel
(git-f61ceeb)
OpenGL core profile shading language version string: 3.30

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https://bugs.freedesktop.org/show_bug.cgi?id=93300

--- Comment #1 from Ilia Mirkin <imirkin at alum.mit.edu> ---
Thanks for testing :) I find it difficult to believe that NV50_PROG_OPTIMIZE=0
wouldn't fix the issue -- probably you just don't have a debug mesa
build.

However I find it easy to believe that this commit breaks something, esp on
nv50, as that (a) has a lot more restrictions and (b) has separate address
registers. Will investigate the trace to see what's up.

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https://bugs.freedesktop.org/show_bug.cgi?id=93300

--- Comment #2 from Ilia Mirkin <imirkin at alum.mit.edu> ---
Created attachment 120418
  --> https://bugs.freedesktop.org/attachment.cgi?id=120418&action=edit
potential patch

Does the attached patch help? If so I'll put something a bit more generic
together.

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https://bugs.freedesktop.org/show_bug.cgi?id=93300

Béla Gyebrószki <gyebro69 at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gyebro69 at gmail.com

--- Comment #3 from Béla Gyebrószki <gyebro69 at gmail.com> ---
(In reply to Ilia Mirkin from comment #1)
> Thanks for testing :) I find it difficult to believe that
NV50_PROG_OPTIMIZE=0 > wouldn't fix the issue -- probably you just
don't have a debug mesa build.
Yes indeed, disabling optimizations works around the problem with a debug build
(originally I tested with a non-debug Mesa build).

(In reply to Ilia Mirkin from comment #2)
> Created attachment 120418 [details] [review]
> potential patch
> 
> Does the attached patch help? If so I'll put something a bit more
generic
> together.
The patch fixes the problem, thank you.

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Ilia Mirkin <imirkin at alum.mit.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Ilia Mirkin <imirkin at alum.mit.edu> ---
Fix pushed:

commit 0f647bd65bae16c7a2dc7a960c96593ad6ab729c
Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Tue Dec 8 16:48:06 2015 -0500

    nv50/ir: check if the target supports the new offset before inlining

    Fixes: abd326e81b (nv50/ir: propagate indirect loads into instructions)
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93300
    Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>

Double-checked that this updated version actually fixed your trace as well.

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