ACK/Cmnt: [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)

Stefan Bader stefan.bader at
Tue Oct 9 07:08:02 UTC 2018

On 09.10.2018 06:54, Hui Wang wrote:
> BugLink:
> 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(-)
The changes themselves are rather incomprehensible and thus not easy to look at.
However all for the same driver and some successful regression testing done. So
with the (->update buglink) buglink replaced by the one from this cover email:

Acked-by: Stefan Bader <stefan.bader at>

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