git bisect start
# good: [1c163f4c7b3f621efff9b28a47abb36f7378d783] Linux 5.0
git bisect good 1c163f4c7b3f621efff9b28a47abb36f7378d783
# bad: [9e98c678c2d6ae3a17cb2de55d17f69dddaa231b] Linux 5.1-rc1
git bisect bad 9e98c678c2d6ae3a17cb2de55d17f69dddaa231b
# good: [e266ca36da7de45b64b05698e98e04b578a88888] Merge tag 'staging-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
git bisect good e266ca36da7de45b64b05698e98e04b578a88888
# bad: [36011ddc78395b59a8a418c37f20bcc18828f1ef] Merge tag 'gfs2-5.1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
git bisect bad 36011ddc78395b59a8a418c37f20bcc18828f1ef
# bad: [4b057e73f28f1df13b77b77a52094238ffdf8abd] Merge tag 'drm-misc-fixes-2019-02-22' of git://anongit.freedesktop.org/drm/drm-misc into drm-next
git bisect bad 4b057e73f28f1df13b77b77a52094238ffdf8abd
# good: [c09d39166d8a3f3788680b32dbb0a40a70de32e2] drm/i915: Update DRIVER_DATE to 20190207
git bisect good c09d39166d8a3f3788680b32dbb0a40a70de32e2
# bad: [1e92a2261acf48a1db4d5b9ec0437190e59c24f3] Merge tag 'exynos-drm-next-for-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into drm-next
git bisect bad 1e92a2261acf48a1db4d5b9ec0437190e59c24f3
# good: [24ba59501257f35b4e1adde9c643f3d149e44084] drm/amdgpu: Add APTX quirk for Lenovo laptop
git bisect good 24ba59501257f35b4e1adde9c643f3d149e44084
# good: [ba9877e2361c46cae3841181aea61e55fc2309b9] drm/bridge: dw-hdmi: add support for YUV420 output
git bisect good ba9877e2361c46cae3841181aea61e55fc2309b9
# bad: [10117450735c7a7c0858095fb46a860e7037cb9a] drm/amd/display: add -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines
git bisect bad 10117450735c7a7c0858095fb46a860e7037cb9a
# good: [4ef9f1ec837be562b42a1c0f196c4ef371b2ed84] drm/amd/display: Let updates with no scaling changes be fast
git bisect good 4ef9f1ec837be562b42a1c0f196c4ef371b2ed84
# bad: [8635c5a784105af8b833c43bf22cbabd6e64a8f1] revert "drm/amd/display: Add condition to sync eDP SW status and HW status"
git bisect bad 8635c5a784105af8b833c43bf22cbabd6e64a8f1
# bad: [07772b0715122222d5a3669fd794ac817ee1617c] drm/amd/display: Update DMCU versioning mechanism
git bisect bad 07772b0715122222d5a3669fd794ac817ee1617c
# good: [8a48b44cd00f10e83f573b9028d11bd90a36de26] drm/amd/display: Call into DC once per multiplane flip
git bisect good 8a48b44cd00f10e83f573b9028d11bd90a36de26
# bad: [b2e85302494a6b7d3a3006c8d80a729377600628] drm/amd/display: Know what a pageflip is
git bisect bad b2e85302494a6b7d3a3006c8d80a729377600628
# bad: [bc7f670ee04cd619f8c4627c37d77b3618bc5edd] drm/amd/display: Perform plane updates only when needed
git bisect bad bc7f670ee04cd619f8c4627c37d77b3618bc5edd
# first bad commit: [bc7f670ee04cd619f8c4627c37d77b3618bc5edd] drm/amd/display: Perform plane updates only when needed

------

bc7f670ee04cd619f8c4627c37d77b3618bc5edd is the first bad commit
commit bc7f670ee04cd619f8c4627c37d77b3618bc5edd
Author: David Francis <David.Francis@amd.com>
Date:   Wed Dec 19 10:45:16 2018 -0500

    drm/amd/display: Perform plane updates only when needed
    
    [Why]
    Our old logic: if pageflip, update freesync and plane address.
    Otherwise, update everything.
    This over-updated on non-pageflip cases, and it failed to
    update if pageflip and non-pageflip changes occurred on
    the same commit
    
    [How]
    Update flip_addrs on pageflips.
    Update scaling_info when it changes.
    Update color fields on color changes.
    Updates plane_info always because we don't have a good way of
    knowing when it needs to be updated.
    
    Unfortunately, this means that every stream commit involves two
    calls into DC.  In particular, on pageflips there is a second,
    pointless update that changes nothing but costs several
    microseconds (about a 50% increase in time taken). The update is
    fast, but there are comparisons and some useless programming.
    
    Leave TODOs indicating dissatisfaction.
    
    Signed-off-by: David Francis <David.Francis@amd.com>
    Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
    Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
    Acked-by: Leo Li <sunpeng.li@amd.com>
    Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

:040000 040000 a34ada118cb7e9219ea1badf43c1b01a4ebfae9d f1e267120d78fe64b5bf26845e0d940ec4fc0243 M	drivers