[SRU][B/OEM-B][PATCH 0/3] screen displays abnormally on the lenovo M715 with the AMD GPU (Radeon Vega 8 Mobile, rev ca, 1002:15dd)

[Hui Wang]

BugLink: https://bugs.launchpad.net/bugs/1791569

These patches are in the 4.16-rcN already, no need to send them to cosmic.

[Impact]
On the machine of Lenovo M715, there is an AMD GPU (1022:15dd rev ca), when it
switchs to amdgpufb, the screen displays abnormally, we tested with a couple monitors,
all of them can reproduce this issue.

[Fix]
Backported 3 patches from mainline kernel, all of them focus on the change of
disable_vga(). After applying these 3 patches, the issue disappears.


[Test Case]
boot the system, run glxgears, everything works well

[Regression Potential]
Very low, these patches come from upstream, and I have tested them on at least 6 different
lenovo machines and those machines have different AMD GPUs on them, all of them worked
as well as before.



Bhawanpreet Lakha (1):
  drm/amd/display: Fix takover from VGA mode

Clark Zheng (1):
  drm/amd/display: Refine disable VGA

Eric Yang (1):
  drm/amd/display: early return if not in vga mode in disable_vga

 drivers/gpu/drm/amd/display/dc/dce/dce_hwseq.h     | 17 ++++++++++++++-
 .../drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c  | 24 ++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

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2.7.4