Same problem here: Laptop is a HP 255 G6 based on AMD E2-9000e, Ubuntu is 18.04 64 bits, kernel 4.15.0-45-generic, wide monitor is LG LG 25UM58-P, 2560x1080.
It does not always flicker, but it does when playing video or when using applications in full screen mode (or in general when using most of the surface of the wide screen). Monitor is connected through HDMI, other monitors with lower resolutions do not flicker. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1791312 Title: ubuntu 18.04 flickering screen with Radeon X1600 Status in linux package in Ubuntu: Confirmed Bug description: my laptop: HP Compaq nx9420 my grafic card: 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV530/M56-P [Mobility Radeon X1600] (prog-if 00 [VGA controller]) attachment: the bug-apport-file Description: I start ubuntu 18.04 LTS (Kernel 22.214.171.124) in textmode; -> as soon as the kernel-module radeon.ko is loaded the screen starts flickering when starting the grafic-mode the flickering continues; so the screen is unusable. when setting the option "radeon.modeset=0" (thus: not use radeon drivers) the screen does not flicker but the resolution is limited to 1400x1050 (instead of natural 1680x1050) so I can not use this as work-around when using the old ubuntu 14.04.05 LTS (Kernel 3.13.0-157) the screen is o.k. NO flickering in textmode, nice grafic, NO flickering xrandr tells: 1680x1050 60.1 so I must stay on old ubuntu 14.04.05 ??? To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1791312/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : email@example.com Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp