Created attachment 686112 [details]
Log-files: hwinfo and journalctl

Hello,

I'm actually not sure if it's a bug in openSuse Tumbleweed, KDE, or Mesa or
something else. When I start the notebook I see a normal booting screen (black
with three green dots) and the KDE login screen appears.

Now the screen begins to flash between black screen and normal picture. It's
not screen tearing like I know from vsync-errors, but it flashes about 5 to 10
times a second and it happens on the whole screen at once. When I move the
mouse the screen flashes about up to 30 times a second. When Firefox starts the
screen doesn't flash as some elements in Firefox rotating. When the mouse
stands still or Firefox finished loading, it flashes 5 to 10 times as before.
In general when I click an application the flashing wents away until the menus
are loaded. Then there's no change in the screen rendering anymore and it
flashes like before.

When I switch to TTY1 I can use the console as normal, there is no flashing.
Back to TTY7 and it flashes again. Logging in to KDE doesn't helped. I also
tested different settings in the KDE compositor settings with OpenGL 2, OpenGL
3, XRender. I have also tested the vsync setting "fullscreen repaint" (or
something lika that, I'm using the german KDE version)

My hardware: Toshiba Satellite P70-B-121
CPU and internal GPU: Intel Core i7-4720HQ
Discrete GPU: AMD Radeon HD 8870M / R9 M270X/M370X --> Venus XT
OS: Tumbleweed, installed in June and the bug still exists in the updated
package versions from today

I have attached some files from hwinfo and journalctl, I hope this helps!
Please tell me if you need more information or if I should test something else.

Regards,
Martin