Bug 69525 - [GM45, bisected] Piglit tex-shadow2drect fails
Summary: [GM45, bisected] Piglit tex-shadow2drect fails
Status: RESOLVED FIXED
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/DRI/i965 (show other bugs)
Version: git
Hardware: Other All
: medium normal
Assignee: Eric Anholt
QA Contact:
URL:
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Keywords: regression
Depends on:
Blocks:
 
Reported: 2013-09-18 12:33 UTC by Pavel Ondračka
Modified: 2013-09-21 23:56 UTC (History)
2 users (show)

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Description Pavel Ondračka 2013-09-18 12:33:26 UTC
I recently did some piglit testing and noticed two old unreported regressions on my GM45 in tests/spec/arb_fragment_program_shadow/tex-shadow2drect.shader_test and tests/spec/arb_fragment_program_shadow/txp-shadow2drect.shader_test

Its caused by commit 
commit 97615b2d8c7c3cea6fd3a43bcb1739a96e2046c4
Author: Eric Anholt <eric@anholt.net>
Date:   Mon Aug 27 14:35:01 2012 -0700

    i965: Replace brw_wm_* with dumping code into the fs_visitor.
    
    This makes a giant pile of code newly dead.  It also fixes TXB on newer
    chipsets, which has been totally broken (I now have a piglit test for that).
    It passes the same set of Ian's ARB_fragment_program tests.  It also improve
    high-settings ETQW performance by 3.2 +/- 1.9% (n=3), thanks to better
    optimization and having 8-wide along with 16-wide shaders.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=24355
    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

Another regression from that commit was in the past tracked in bug 55825, so I just made a comment in bug 55825 comment 5, cause I thought it is a duplicate. Bug 55825 was however closed some time ago and this regression is still present. 

BTW the tests doesn't fail everytime, there is some chance of pass (like 5-10 passes in 100 runs).

./bin/shader_runner tests/spec/arb_fragment_program_shadow/tex-shadow2drect.shader_test -auto
Output:
Probe at (0,25)
  Expected: 1.000000 1.000000 1.000000 1.000000
  Observed: 0.000000 0.000000 0.000000 1.000000
Probe at (225,249)
  Expected: 1.000000 1.000000 1.000000 1.000000
  Observed: 0.000000 0.000000 0.000000 1.000000

./bin/shader_runner tests/spec/arb_fragment_program_shadow/txp-shadow2drect.shader_test -auto
Output:
Probe at (0,25)
  Expected: 1.000000 1.000000 1.000000 1.000000
  Observed: 0.000000 0.000000 0.000000 1.000000
Probe at (225,249)
  Expected: 1.000000 1.000000 1.000000 1.000000
  Observed: 0.000000 0.000000 0.000000 1.000000

GPU:GM45
Mesa: ec44d56a5b20632bcd4cb19ae6fa5d615df4149f
Kernel: 3.10.11-100.fc18.x86_64
Libdrm: 2.4.45-1.fc18
Comment 1 Eric Anholt 2013-09-18 18:45:11 UTC
I think I see the bug (m4 not getting set to 0)
Comment 2 Eric Anholt 2013-09-18 19:35:52 UTC
Nope, that wasn't it, but I've got a patch to test now.
Comment 3 Eric Anholt 2013-09-21 23:56:45 UTC
commit 938956ad52bc7659212b5877080967d4af0aad81
Author: Eric Anholt <eric@anholt.net>
Date:   Wed Sep 18 12:32:31 2013 -0700

    i965/gen4: Fix fragment program rectangle texture shadow compares.


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