[Bug 29914] New: [1.3.15-1.4_rc3] Civ4 too dark: EXT_texture_sRGB_decode broken on GM45 (again?)

http://bugs.winehq.org/show_bug.cgi?id=29914

Bug #: 29914
           Summary: [1.3.15-1.4_rc3] Civ4 too dark:
                    EXT_texture_sRGB_decode broken on GM45 (again?)
           Product: Wine
           Version: 1.4-rc3
          Platform: x86-64
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: directx-d3d
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
    Classification: Unclassified

Created attachment 38913
  --> http://bugs.winehq.org/attachment.cgi?id=38913
wine regression test log

Starting a new bug after hijacking bug 23498 already. Two screenshots of the
problem can be found there.

System:
Intel GMA 4500, Gentoo amd64, kernel-3.2.6/drm-3.3_rc3
Latest Intel userspace drivers
Mesa 32bit libs: 7.11.2

Summary:
- Starting Civilization IV from wine-1.3.15 onwards (wine.git 12/02/15) it
paints too dark images as soon as accessing the main menu.
- The rendering is less, but still too dark with Hardware Vertex-/Pixelshader
switched off (a wine graphics option present in 1.3.15 but not anymore)
- As pointed out in the previous bug, a similar/the same issue should have
already been fixed in mesa-7.11 ->
https://bugs.freedesktop.org/show_bug.cgi?id=35373

Temporary solution: 
MESA_EXTENSION_OVERRIDE="-GL_EXT_texture_sRGB_decode", taken from the linked
freedesktop bug, fixes the problem