Bug 64608

Summary: [PNV Bisected]Piglit spec/glsl-1.10/execution/variable-indexing/fs-temp-mat4-col-row-wr fail
Product: Mesa Reporter: lu hua <huax.lu>
Component: Drivers/DRI/i915Assignee: Ian Romanick <idr>
Status: VERIFIED FIXED QA Contact:
Severity: major    
Priority: medium CC: xunx.fang
Version: unspecified   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description lu hua 2013-05-15 02:02:22 UTC 
System Environment:
--------------------------
Arch:             i386
Platform:         Pineview
Libdrm:		(master)2.4.44-9-g96e90aabc4c0238de2f2d245899f991a3b996587
Mesa:		(master)888fc7a89197972aac614fc19d1c82ed1adbb3f2
Xserver:(master)xorg-server-1.14.99.1-81-g2f1aedcaed8fd99b823d451bf1fb02330c078f67
Xf86_video_intel:(master)2.21.6-31-g2217f6356b53263b6ce8f92b5c29c0614d4ef2a5
Cairo:		(master)728e58e60f89076f626329ee3f006f011783f90b
Libva:		(staging)0139a11ba23f8b2aa0d2ed36336c4df23d54390c
Libva_intel_driver:(staging)0a5cfdab47c788569feb0a3e4293906687523f88
Kernel:	(drm-intel-nightly) fa643cb2d17c011fdddd5e0cc8fc808e097dc5bb

Bug detailed description:
-------------------------
It fails on pineview with mesa master branch. It works well on 9.1 branch.
Following cases also fail, and have same bisect commit:
spec_glsl-1.10_execution_variable-indexing_fs-temp-array-mat4-col-row-wr
spec_glsl-1.20_execution_variable-indexing_fs-temp-array-mat4-col-row-wr
spec_glsl-1.20_execution_variable-indexing_fs-temp-mat4-col-row-wr

Bisect shows:3acb21517b3a23cf1044531e96d9741bd1c122c3 is the first bad commit.
commit 3acb21517b3a23cf1044531e96d9741bd1c122c3
Author:     Ian Romanick <ian.d.romanick@intel.com>
AuthorDate: Fri Mar 15 18:08:22 2013 -0700
Commit:     Ian Romanick <ian.d.romanick@intel.com>
CommitDate: Mon May 13 12:05:19 2013 -0700

    glsl: Generate ir_binop_vector_extract for indexing of vectors

    Now ir_dereference_array of a vector will never occur in the RHS of an
    expression.

    v2: Add back the { } around the if-statement body to make it more
    readable.  Suggested by Eric.

    Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
    Reviewed-by: Eric Anholt <eric@anholt.net>
    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

output:
Probe at (10,10) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (10,25) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (10,40) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (10,55) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (25,10) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (25,25) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (25,40) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (25,55) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (40,10) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (40,25) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (40,40) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (40,55) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (55,10) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (55,25) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (55,40) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
Probe at (55,55) 
Expected: 0.000000 1.000000 0.000000 
Observed: 1.000000 0.000000 0.000000 
PIGLIT: {'result': 'fail' } 

Reproduce steps:
----------------
1. xinit
2. ./bin/shader_runner tests/spec/glsl-1.10/execution/variable-indexing/fs-temp-mat4-col-row-wr.shader_test -auto
Comment 1 Gordon Jin 2013-05-24 05:13:24 UTC 
Ian, can you reproduce?
Comment 2 Kenneth Graunke 2013-07-27 02:28:14 UTC 
I can confirm the bisect - it works before that commit, and fails on it.

I also observed that it works with either no_rast=true or LIBGL_ALWAYS_SOFTWARE=1, so presumably the Mesa IR being generated is good.  Sounds like the i915 assembly is bad.

I don't plan on investigating further, though...the i915c driver confuses me.
Comment 3 Ian Romanick 2013-07-27 05:39:58 UTC 
I suspect the problem is changing the compiler to not generate the vectorized compares makes it take too many instructions for i915.  That's just a hunch, though.

I will take care of this for 9.2.
Comment 4 Ian Romanick 2013-08-22 03:49:46 UTC 
It turned out to be the opposite of my intuition.  The changes in the patch caused *more* tests to run in hardware on i915.  The problem is the tests require more precision that i915 can deliver with its 24-bit floats.  I have sent a patch to the piglit mailing list to relax the precision requirement (these tests are not about the precision of the distance() function anyway!) and a patch to the Mesa list that makes even more tests run in hardware.

http://lists.freedesktop.org/archives/piglit/2013-August/006903.html
http://lists.freedesktop.org/archives/mesa-dev/2013-August/043650.html

I am removing this bug from the release tracker because it's not a real regression.
Comment 5 Kaveh 2014-08-05 01:06:32 UTC 
Please confirm that this is seen on an SNB or newer platform.
Comment 6 lu hua 2014-08-05 05:28:43 UTC 
(In reply to comment #5)
> Please confirm that this is seen on an SNB or newer platform.

It passes on all platforms. Test on latest mesa master branch.
Comment 7 lu hua 2014-08-06 04:53:45 UTC 
Fixed.
Comment 8 lu hua 2014-08-06 04:53:59 UTC 
Verified.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.