Created attachment 134972 [details]
regressed steam menu

Steam has some very bad flickering of menu items in latest mesa git. 

OpenGL renderer string: AMD Radeon HD 7900 Series (TAHITI / DRM 3.23.0 / 4.13.0-2-amd-staging-drm-next-git, LLVM 6.0.0)
OpenGL core profile version string: 4.5 (Core Profile) Mesa 17.3.0-devel (git-0fdd531457)

Bisected to:

2f4705afde707e8eb41b9414c25df91aa1ea2fb3 is the first bad commit
commit 2f4705afde707e8eb41b9414c25df91aa1ea2fb3
Author: Marek Olšák <marek.olsak@amd.com>
Date:   Sun Oct 8 03:44:07 2017 +0200

    radeonsi: if there's just const buffer 0, set it in place of CONST/SSBO pointer
    
    SI_SGPR_CONST_AND_SHADER_BUFFERS now contains the pointer to const buffer 0
    if there is no other buffer there.
    
    Benefits:
    - there is no constbuf descriptor upload and shader load
    
    It's assumed that all constant addresses are within bounds. Non-constant
    addresses are clamped against the last declared CONST variable.
    This only works if the state tracker ensures the bound constant buffer
    matches what the shader needs.
    
    Once we get 32-bit pointers, we can only do this for user constant buffers
    where the driver is in charge of the upload so that it can guarantee a 32-bit
    address.
    
    The real performance benefit might not be measurable.
    
    These apps get 100% theoretical benefit in all shaders (except where noted):
    - antichamber
    - barman arkham origins
    - borderlands 2
    - borderlands pre-sequel
    - brutal legend
    - civilization BE
    - CS:GO
    - deadcore
    - dota 2 -- most shaders
    - europa universalis
    - grid autosport -- most shaders
    - left 4 dead 2
    - legend of grimrock
    - life is strange
    - payday 2
    - portal
    - rocket league
    - serious sam 3 bfe
    - talos principle
    - team fortress 2
    - thea
    - unigine heaven
    - unigine valley -- also sanctuary and tropics
    - wasteland 2
    - xcom: enemy unknown & enemy within
    - tesseract
    - unity (engine)
    
    Changed stats only:
        SGPRS: 2059998 -> 2086238 (1.27 %)
        VGPRS: 1626888 -> 1626904 (0.00 %)
        Spilled SGPRs: 7902 -> 7865 (-0.47 %)
        Code Size: 60924520 -> 60982660 (0.10 %) bytes
        Max Waves: 374539 -> 374526 (-0.00 %)
    
    Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

:040000 040000 7b660ccfb110c80ecd9b3d2f7f06ace5380cb76f d8ddc8515150a84131e566c4ddafb05d3d7be0a7 M	src


Confirmed bad commit by reverting it.