Bug 91047

Summary: [SNB Bisected] Messed up Fog in Super Smash Bros. Melee in Dolphin
Product: Mesa Reporter: Link Mauve <bugs>
Component: Drivers/DRI/i965Assignee: Matt Turner <mattst88>
Status: RESOLVED FIXED QA Contact: Intel 3D Bugs Mailing List <intel-3d-bugs>
Severity: normal    
Priority: medium    
Version: 10.6   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: apitrace of that issue
p.patch
p.patch

Description Link Mauve 2015-06-21 22:51:18 UTC
Created attachment 116638 [details]
apitrace of that issue

After a round of bisect, “f7df169ba13d22338e9276839a7e9629ca0a6b4f is the first bad commit”, “i965/fs: Implement integer multiply without mul/mach.”
Comment 1 Matt Turner 2015-06-22 03:12:17 UTC
Can you confirm that you have this commit (on the 10.6 branch), and that the problem still exists with it?

commit 230891cc9c24744cbe59cc40a748a69a6b89edf6
Author: Matt Turner <mattst88@gmail.com>
Date:   Wed May 27 10:44:45 2015 -0700

    i965/fs: Fix lowering of integer multiplication with cmod.
    
    If the multiplication's result is unused, except by a conditional_mod,
    the destination will be null. Since the final instruction in the lowered
    sequence is a partial-write, we can't put the conditional mod on it and
    we have to store the full result to a register and do a MOV with a
    conditional mod.
    
    Cc: "10.6" <mesa-stable@lists.freedesktop.org>
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90580
    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
    (cherry picked from commit 0596134410a0decc2f6bba77bfedb82d308aabbe)

Can you reproduce with master?
Comment 2 Link Mauve 2015-06-22 08:05:13 UTC
I actually found the bug in 10.6 (from the ArchLinux repository) then switched to mesa-git, which tracks master, to do the bisection.

And I do have 0596134410a0decc2f6bba77bfedb82d308aabbe in this branch, which didn’t fix it.
Comment 3 Matt Turner 2015-06-22 17:52:50 UTC
Created attachment 116658 [details] [review]
p.patch

Please try this patch. I expect it fixes the problem.
Comment 4 Matt Turner 2015-06-22 17:56:45 UTC
Created attachment 116659 [details] [review]
p.patch

Sorry, this one will actually apply to master. :)
Comment 5 Link Mauve 2015-06-22 19:11:04 UTC
It fixed it, thanks. :)
Comment 6 Matt Turner 2015-06-23 19:49:49 UTC
Thanks a lot for the bug report and testing the patch. I've committed it as

commit a49328d58d1e3e143f9434976d9f3574acefc4ea
Author: Matt Turner <mattst88@gmail.com>
Date:   Mon Jun 22 10:59:33 2015 -0700

    i965/fs: Don't mess up stride for uniform integer multiplication.

and tagged it for the 10.6 branch, so it should be in 10.6.1.

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