Bug 45872

Summary: [bisected PNV] oglc mustpass(basic.stipple) regressed on pineview
Product: Mesa Reporter: fangxun <xunx.fang>
Component: Drivers/DRI/i915Assignee: Ian Romanick <idr>
Status: VERIFIED FIXED QA Contact:
Severity: major    
Priority: high    
Version: git   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Bug Depends on:    
Bug Blocks: 42993    
Attachments: Proposed work-around

Description fangxun 2012-02-10 01:20:47 UTC 
System Environment:
--------------------------
Arch:           i386
Platform:       Pineview
Libdrm:         (master)2.4.31-1-g2cfac57d364d0166ed9472b086c16aea376f495a
Mesa:           (8.0)e86d90eb208292916c8a04c5d75499492003dd16
Xserver:      (server-1.11-branch)xorg-server-1.11.3
Xf86_video_intel:  (master)2.17.0-644-g4d8369f8e60fd4f5a0ef49f3e9866ea5ecb21927
Kernel:         (drm-intel-fixes) 617cf884810b44384fe8e9431e9babeb80a2ff37

Bug detailed description:
------------------------- 
It fails at mesa master and mesa 8.0 branch on pineview. Below cases also fail:
linestip(basic.allCases)
tristip(basic.fan) 
tristip(basic.strip) 
tristip(basic.triangles)
polystip(basic.allCases)

Bisect shows 85a52bf7b5f5f0317d15a51f94f294fc5e72d936 is the first bad commit.
commit 85a52bf7b5f5f0317d15a51f94f294fc5e72d936
Author:     Ian Romanick <ian.d.romanick@intel.com>
AuthorDate: Thu Jan 19 17:29:37 2012 -0800
Commit:     Ian Romanick <ian.d.romanick@intel.com>
CommitDate: Fri Jan 27 18:02:42 2012 -0800

    swrast: Use fixed-function processing instead _TexEnvProgram for DrawPixels

    This is a hack to work around drivers such as i965 that:

        - Set _MaintainTexEnvProgram to generate GLSL IR for
          fixed-function fragment processing.
        - Don't call _mesa_ir_link_shader to generate Mesa IR from the
          GLSL IR.
        - May use swrast to handle glDrawPixels.

    Since _mesa_ir_link_shader is never called, there is no Mesa IR to
    execute.  Instead do regular fixed-function processing.

    Even on platforms that don't need this, the software fixed-function
    code is much faster than the software shader code.

    NOTE: This is a candidate for the 8.0 branch.

    
Reproduce steps:
----------------
1. start X
2. ./oglconform -z -s -suite all -v 2 -test mustpass basic.stipple
Comment 1 Ian Romanick 2012-02-10 11:54:56 UTC 
*** Bug 45878 has been marked as a duplicate of this bug. ***
Comment 2 Paul Berry 2012-02-10 13:05:46 UTC 
The following Piglit failures also bisect to this commit:
general/linestipple 
glean/paths 
spec/OpenGL_1.2_texwrap-3D-bordercolor 
spec/OpenGL_1.2_texwrap-3D-proj-bordercolor 
texturing/texrect-many
Comment 3 Ian Romanick 2012-02-10 16:16:18 UTC 
Created attachment 56892 [details] [review]
Proposed work-around
Comment 4 Ian Romanick 2012-02-10 16:18:38 UTC 
*** Bug 45876 has been marked as a duplicate of this bug. ***
Comment 5 Ian Romanick 2012-02-15 14:53:16 UTC 
Fixed on 8.0 branch by:

commit ff1d9450321d5fe164611f819ee299706d9cbe02
Author: Ian Romanick <ian.d.romanick@intel.com>
Date:   Fri Feb 10 16:00:27 2012 -0800

    swrast: Only avoid empty _TexEnvPrograms
    
    If the generated shader for _TexEnvProgram is empty, force the use of
    the fixed-function code.  Otherwise, go ahead and use the shader.
    This works around a mysterious issue on i915 where fixed-function
    software fallbacks are not working correctly.
    
    This isn't really the fix we want, but it works around the issue.
    
    Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
    Reviewed-by: Chad Versace <chad.versace@linux.intel.com>
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45872
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45876
    (cherry picked from commit 3e22d4e5fc32dafcb9669a9d6376323aa88e300c)
Comment 6 fangxun 2012-03-14 20:59:28 UTC 
Verified with mesa master branch(ead3589aa) and mesa 8.0 branch(437ed1faaf6).

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