It's an old patch but does drm-fixes-4.16 have this patch

commit e92b44fdee3ec0b679bacdb9c7e95e55699167f0 Refs: v4.14-rc3-1871-ge92b44fdee3e Author: Tony Cheng <> AuthorDate: Thu Oct 5 14:38:46 2017 -0400 Commit: Alex Deucher <> CommitDate: Sat Oct 21 16:52:21 2017 -0400

    drm/amd/display: default force_single_disp_pipe_split = 1 on RV

    1080p idle, stutter efficiency goes up from 95.8% to 97.8%
    result in 5mW saving from APU and 8mW saving from DDR4

Signed-off-by: Tony Cheng <> Reviewed-by: Yongqiang Sun <> Acked-by: Harry Wentland <> Signed-off-by: Alex Deucher <>



On 03/07/2018 02:12 PM, Harry Wentland wrote:
On 2018-03-07 12:38 PM, KARBOWSKI Piotr wrote:
On 2018-03-07 17:48, KARBOWSKI Piotr wrote:
On 2018-03-07 17:14, Harry Wentland wrote:
Pushed a drm-fixes-4.16 branch (based on Alex's) to my FDO repo 
at  but I don't have a Raven 
system setup to test this at the moment.

Tom, or Piotr, would you be able to check that the fix works as intended on 
that branch?

Tested that branch, confirmed that the VGA patch is there but I got the 
original result of broken video. Rebooted few times. It seems that my issue was 
not the VGA turnover afterall. I will re-test it with vanilla 
amd-staging-drm-next of git:// without the 
VGA patch and update you.

Thanks for testing.

What do you mean with broken video? I tried going back in the email thread but 
I'm not 100% clear what you mean by this.

BTW, drm-fixes-4.16 are fixes we intend to get into the 4.16 upstream kernel. 
amd-staging-drm-next is our development tree and quite a bit farther ahead in 
development. I'm trying to find fixes to backmerge to 4.16 to make everyone 
happy when it releases.


I re-tested original tree of git:// on 
branch amd-staging-drm-next and got the 'double screen' glitches, then I 
applied the patch Tom sent me as the very first response to this thread and 
then it indeed fixed it. So the VGA takeover patch is needed it, it seems.

I triple checked and build the images and the drm-fixes-4.16 of 
git:// does not fix the problem for me.

So far only amd-staging-drm-next with 
0001-drm-amd-display-Fix-takeover-from-VGA-mode.patch does the trick. One thing 
worth note is that the amd-staging-drm-next goes as `rc1` where yours fork 
Harry appears to be rc3, no idea if it's related or not.

-- Piotr.
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