Bug 46489

Summary: [Bisected ILK] Piglit bugs/point-sprite regressed
Product: Mesa Reporter: lu hua <huax.lu>
Component: Drivers/DRI/i965Assignee: Kenneth Graunke <kenneth>
Status: VERIFIED FIXED QA Contact:
Severity: major    
Priority: high CC: eric, xunx.fang
Version: git   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description lu hua 2012-02-22 18:19:20 UTC 
System Environment:
--------------------------
Arch:           i386
Platform:       Ironlake
Libdrm:		(master)2.4.31-5-g23eeb7e1e45417a5a84f826286dd982dba440cd3
Mesa:		(master)ab79d2be2e1288d4044a8b4ef356991625a176f5
Xserver:	(master)xorg-server-1.11.99.903-1-gd53235af85d50774c68347720ce132daf9a5bc49
Xf86_video_intel:(master)2.17.0-679-gfe6602cbbc4eed1b88ac731a30b46cc970ea444f
Kernel:	 (drm-intel-next-queued) de67cba65944f26c0f147035bd62e30c5f456b96

Bug detailed description:
-----------------------------
It fails on Ironlake with Mesa master branch. It does not happen with Mesa 8.0 branch.

Bisect shows f0cecd43d6b6d3f5def3fd43b9c95baaf3be9b16 is the first bad commit.
commit f0cecd43d6b6d3f5def3fd43b9c95baaf3be9b16
Author:     Eric Anholt <eric@anholt.net>
AuthorDate: Mon Feb 13 10:08:23 2012 -0800
Commit:     Eric Anholt <eric@anholt.net>
CommitDate: Tue Feb 21 11:54:02 2012 -0800

    i965: Move VUE map computation to once at VS compile time.

    With this and the previous patch, 640x480 nexuiz is running 0.169118%
    +/- 0.0863696% faster (n=121).  On a VS state change microbenchmark,
    performance is increased 8.28645% +/- 0.460478% (n=52).

    v2: Fix CACHE_NEW_VS comment.

    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

Following oglc cases also fails on Ironlake,and have same commint:
pointsprite(basic.points.upper_left.min)
pointsprite(basic.points.upper_left.medium)
pointsprite(basic.points.lower_left.min)
pointsprite(basic.points.lower_left.medium)
pointsprite(basic.points.lower_left.max)
pointsprite(basic.mode.immediate.points)
pointsprite(basic.mode.compile.points)
pointsprite(basic.mode.compile_execute.points)
pointsprite(basic.mode.calllist.points)
pointsprite(basic.mode.calllist.triangles)
pointsprite(basic.position.0_0.points)
pointsprite(basic.position.0_1.points)
pointsprite(basic.position.0_2.points)
pointsprite(basic.position.1_0.points)
pointsprite(basic.position.1_1.points)
pointsprite(basic.position.1_2.points)
pointsprite(basic.position.2_0.points)
pointsprite(basic.position.2_1.points)
pointsprite(basic.position.2_2.points)
pointsprite_vcg(advanced.test1)
pointsprite_vcg(advanced.test6)
pointsprite_vcg(advanced.test8)
pointsprite_vcg(advanced.test7)

Reproduce steps:
----------------------------
1. Start  X
2. Run: ./point-sprite -auto
Comment 1 Gordon Jin 2012-03-31 18:25:28 UTC 
Ian, Eric?
Comment 2 Kenneth Graunke 2012-08-05 08:56:55 UTC 
I can confirm that reverting this commit on top of latest master makes the test pass.  Still not sure why.
Comment 3 Kenneth Graunke 2012-08-05 09:39:46 UTC 
It turns out that allocating all your slots before computing the VUE map helps. :)

Patch on mailing list:
http://lists.freedesktop.org/archives/mesa-dev/2012-August/025184.html
Comment 4 Kenneth Graunke 2012-08-06 22:33:46 UTC 
commit caa4ae5d7d864278ffbf5dbd9c25bb2932e91fc5
Author: Kenneth Graunke <kenneth@whitecape.org>
Date:   Sun Aug 5 02:30:38 2012 -0700

    i965: Allocate dummy slots for point sprites before computing VUE map.
    
    Commit f0cecd43d6b6d moved the VUE map computation to be only once, at
    VS compile time.  However, it did so in slightly the wrong place: it
    made the one call to brw_vue_compute_map happen right before the
    allocation of dummy slots for replaced point sprite coordinates, causing
    a different VUE map to be generated (at least on Ironlake).
    
    Fixes a regression in Piglit's point-sprite test on Ironlake.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=46489
    Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
    Reviewed-by: Eric Anholt <eric@anholt.net>
Comment 5 lu hua 2012-08-08 01:53:35 UTC 
Verified. Fixed by commit caa4ae5d7d864278ffbf5dbd9c25bb2932e91fc5

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.