[Bug 98784] Talos Principle rendering flickering garbage on start instead of its logo and loading squares

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=98784

--- Comment #7 from Samuel Pitoiset <samuel.pitoiset at gmail.com> ---
Can you try with LIBGL_DRI3_DISABLE=1 ? This will use DRI2 and it should fix
the flickering.

After bisecting, the first bad commit seems to be:

commit d3d33918c79d9e87aedaf6f70ed39f75eed262a0
Author: Michel Dänzer <michel.daenzer at amd.com>
Date:   Wed Aug 17 17:02:04 2016 +0900

    loader/dri3: Overhaul dri3_update_num_back

    Always use 3 buffers when flipping. With only 2 buffers, we have to wait
    for a flip to complete (which takes non-0 time even with asynchronous
    flips) before we can start working on the next frame. We were previously
    only using 2 buffers for flipping if the X server supports asynchronous
    flips, even when we're not using asynchronous flips. This could result
    in bad performance (the referenced bug report is an extreme case, where
    the inter-frame stalls were preventing the GPU from reaching its maximum
    clocks).

    I couldn't measure any performance boost using 4 buffers with flipping.
    Performance actually seemed to go down slightly, but that might have
    been just noise.

    Without flipping, a single back buffer is enough for swap interval 0,
    but we need to use 2 back buffers when the swap interval is non-0,
    otherwise we have to wait for the swap interval to pass before we can
    start working on the next frame. This condition was previously reversed.

    Cc: "12.0 11.2" <mesa-stable at lists.freedesktop.org>
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97260
    Reviewed-by: Frank Binns <frank.binns at imgtec.com>
    Reviewed-by: Eric Anholt <eric at anholt.net>
    (cherry picked from commit 1e3218bc5ba2b739261f0c0bacf4eb662d377236)

    Squashed with commit:

    loader/dri3: Always use at least two back buffers

    This can make a significant difference for performance with some extreme
    test cases such as vblank_mode=0 glxgears.

    Fixes: 1e3218bc5ba2 ("loader/dri3: Overhaul dri3_update_num_back")
    Cc: "12.0 11.2" <mesa-stable at lists.freedesktop.org>
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97549
    Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
    Tested-by: Dieter Nützel <Dieter at nuetzel-hh.de>
    (cherry picked from commit dc3bb5db8c81e7f08ae12ea5d3ee999e2afcbfd1)

:040000 040000 aa5cf86f1e98d023f9539a6a15654fd9754101a2
fb92ad057feeb3fbff38d808c71c7e5e1cead9af M      src

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