Bug 199319 - Flickering screen on AMDGPU and DC with Linux 4.16-2
Summary: Flickering screen on AMDGPU and DC with Linux 4.16-2
Status: NEW
Alias: None
Product: Drivers
Classification: Unclassified
Component: Video(DRI - non Intel) (show other bugs)
Hardware: x86-64 Linux
: P1 normal
Assignee: drivers_video-dri
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-04-08 09:10 UTC by rainer
Modified: 2018-12-13 01:25 UTC (History)
11 users (show)

See Also:
Kernel Version: Linux 4.16
Subsystem:
Regression: No
Bisected commit-id:


Attachments

Description rainer 2018-04-08 09:10:11 UTC
Description: I upgraded to Linux 4.16-2 from the Arch Linux testing repository, but since then the screen is flickering with my RX480 and AMDGPU.DC enabled. The flickering is visible especially on Plasma-Wayland as soon as I move the mouse, it is like a bright flickering, not like a graphical corruption. On SDDM or Plasma X11 the flickering is much less frequent, but even there the screen flickers from time to time. I use a 4K display connected via DisplayPort.
A downgrade to Linux 4.15 stable solved this even tough AMDGPU.DC is enabled as well. 
I couldn't reproduce the same issue with my AMD Ryzen 5 2500U Vega APU (1920x1080), so the issue might be related to the RX480 or 4K.


Additional info:
* Linux 4.16-2 from Arch Linux testing
* AMDGPU.DC=1 (kernel parameter)
* 4K display DisplayPort


Steps to reproduce:
1. Ugrade to Linux 4.16.2 with AMDGPU.DC enabled on a RX480
2. Screen is flickering when moving the mouse
Comment 1 Laurent Carlier 2018-04-08 09:21:46 UTC
Same here with RX470 @ 1920x1080 - HDMI
Comment 2 Ed Tomlinson 2018-04-08 13:11:55 UTC
Here too on arch with either mesa 17.3 or 18.0 on 4.16.1-rc with a RX480 4G HDMI (1920x1200)
Comment 3 pmargeti34 2018-04-08 17:01:59 UTC
+1

Arch Linux 4.16 with amdgpu.dc=1
MSI Radeon Rx560 4GB -> LG 2560x1080 panel over HDMI

Flickering doesn't happen if Option "TearFree" "true" isn't set in driver's .conf file or if there is no tearing option ("vsync") selected in KDE system settings->display and monitor->compositor

Running 4.16 with amdgpu.dc=0 removes flickering.
Comment 4 Ed Tomlinson 2018-04-08 20:23:15 UTC
I checked my X conf, no tearfree option is set, using 4.15 I set tearing prevention to never and rebooted into 4.16.1-rc.  

This does NOT stop the flickering here.

Flicking does not occur with 4.15 dc-1 and does with 4.16.

IMO this is a regression.
Comment 5 rainer 2018-04-08 20:32:05 UTC
Thanks for the hint with vsync, but it didn't change anything for me on Plasma-Wayland.

At least I noticed, that the bright flickering on my screen on Plasma-Wayland when moving the mouse appears was due to night shift changing the colours. It worked well on Linux 4.15. But on Linux 4.16 I need to deactivate it so that the flickering on Plasma-Wayland during the mouse movements stops.

With night shift and even vsync disabled, there is now just from time to time a flickering, irregularly.
Comment 6 rainer 2018-04-09 07:50:11 UTC
The flickering that is happening from time to time is probably the same as in the bug report https://bugzilla.kernel.org/show_bug.cgi?id=199101.

So only the flickering when night shift is enabled on Plasma-Wayland seems to be different.
Comment 7 Michel Dänzer 2018-04-09 08:02:33 UTC
Is this the same as bug 199101?
Comment 8 rainer 2018-04-09 09:26:56 UTC
The random flickering every 30 seconds is the same from my point of view. What is different on my setup is that Plasma-Wayland with night shift enabled with a changed color flickers with every mouse movement since Linux 4.16. So the answer is partially.
Comment 9 Mike Lothian 2018-04-09 11:21:52 UTC
I'm seeing this too, also plasma-wayland but with a PRIME Skylake/Tonga setup only Skylake is used on the desktop
Comment 10 Mike Lothian 2018-04-09 11:24:11 UTC
I should add this is 4.16-rc7 (agd5f's 4.18-wip branch) Qt 5.10, KDE frameworks 5.44, Plasma 5.12.4, Xorg 1.19.5 using the modesetting DDX (I'll try the Intel & AMDGPU DDXs tonight.
Comment 11 zxvfxwing 2018-04-09 15:59:45 UTC
Flickering here too: 4.16.0-2-ARCH, RX480, Mesa 18.0.0, x11 (X.Org 1.19.6).
Comment 12 haro41 2018-04-10 12:48:24 UTC
Same here:

Flickering (as described by 'mail'):
4.16.1, R9 380X, Mesa 18.1.0-devel (git-d899826733), X11(1.19.6)
Tried Gnome and XFCE, similar problems.

This problem doesn't occur with:

- older Kernel (4.15.0)
- 3D Fullscreen (Games)
- older GPU (R9 280X)

Maybe a powerplay related problem, since it only affect newer AMD cards?
Comment 13 haro41 2018-04-10 13:00:44 UTC
... have to add:

This problem doesn't occur too with:

- amdgpu.dc=0
Comment 14 haro41 2018-04-10 18:56:33 UTC
linux 4.16.1, R9 380X, Mesa 18.1.0-devel (git-d899826733), X11(1.19.6)

with:

amdgpu.dc=0: no flickering, HDMI audio works

amdgpu.dc=1: flickering, HDMI audio not working
Comment 15 Márcio 2018-04-14 14:18:34 UTC
Same problem here, using linux 4.16.2 on Arch Linux and RX 480 DisplayPort, at 2560 x 1080.

No xorg config set. 

Kernel parameter amdgpu.dc=1

The flickering happens eventualy, but when using nightlight gnome feature it happens more frequently.
Comment 16 Harry Wentland 2018-04-17 18:11:42 UTC
A fix should be in drm-next-4.17 of Alex's git repo at https://cgit.freedesktop.org/~agd5f/linux/?h=drm-next-4.17 and should make it into Linus's tree from there.

That fix should also make it into 4.16 stable.
Comment 17 zxvfxwing 2018-04-18 11:51:31 UTC
(In reply to Harry Wentland from comment #16)
> A fix should be in drm-next-4.17 of Alex's git repo at
> https://cgit.freedesktop.org/~agd5f/linux/?h=drm-next-4.17 and should make
> it into Linus's tree from there.
> 
> That fix should also make it into 4.16 stable.

Good to know! Thank you.
Comment 18 haro41 2018-04-18 17:00:46 UTC
@Harry Wentland,
i am trying kernel 4.17.0-rc1 (patches already merged by linus):

With 'amdgpu.dc=1', i get a black screen now at login (perhaps related to this dc issue). I found 2 new warnings and call traces in kernel log, like:

Apr 18 18:28:41 debian kernel: WARNING: CPU: 10 PID: 345 at drivers/gpu/drm/amd/amdgpu/../display/dc/dm_services.h:132 generic_reg_update_ex+0x102/0x150 [amdgpu]

...
Comment 19 Harry Wentland 2018-04-18 18:14:21 UTC
@haro41, I recommend opening a new bug if you're seeing a different issue, unless you have strong reason to believe it's caused by the fixes for the flickering screen, or otherwise related to it.
Comment 20 haro41 2018-04-23 14:37:46 UTC
This issues (both, the flickering and the black screen) are obviously fixed with kernel 4.17.0-rc2. Thank you.
Comment 21 siyia 2018-12-12 16:46:40 UTC
Hello i also get screen flickering when running 3d games and massive performance drop on Xorg with amdgpu.dc enabled.If i add amdgpu.dc=0 to kernel parameters, Xorgs runs buttery smooth and games do not flicker,my gpu is polaris RX 550 4gb.

Is there any disadvantage to run the gpu with amdgpu DC off? i use an analog vga monitor with an active vga to dvi-d converter and i do not plan to use hdmi in next few years ahead.
Comment 22 siyia 2018-12-12 16:47:04 UTC
Tested both kernels 4.19.x and 4.20rc6

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