As mentioned in the title. Was upgrading from 17.10. Having this screen flickering.

My GPU is AMD RX480

What I did:

  • Search for similar issues for 18.04, can't find any
  • Perform fresh install. Still the same.

Please help. It is very annoying. I can't work.

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10 Answers 10


I solved it myself by using amdgpu.dc=0 as a boot parameter.

To do this, edit the file /etc/default/grub, for example using

sudoedit /etc/default/grub

Find the line beginning GRUB_CMDLINE_LINUX_DEFAULT and add the text amdgpu.dc=0 between the double quotes (""). Leave any other parameters as they are. For example, you may end up with a line like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash amdgpu.dc=0"

Save the file and exit, and then run

sudo update-grub

to write the configuration, and reboot.

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  • Getting a black screen, answer doesn't work any more? – Gabor May 9 '18 at 2:17
  • I had this problem and your solution worked! +1 – Ian Rehwinkel May 17 '18 at 19:20
  • Hi all, if you update to 18.10, you need to reverse the changes or otherwise the flicker will return. – LaoPiSai Oct 30 '18 at 10:54
  • What if you have an Intel integrated GPU? – beruic Apr 21 '19 at 19:15
  • I was having flickering problems in 18.04 (I am using an RX 570 graphics card). The screen was fine normally, but it would start flickering after waking up from suspend. This solution seems to have fixed it. Thanks. – CluelessNoob May 9 '19 at 20:57

I have screen flickering problem when I'm connecting my laptop to my TV. I found that when I change the refresh rate from 60Hz to 59Hz this problem disappear.

Within Xorg (as I know 18.04 uses it by default) you can change the refresh rate by the help of xrandr:

0. First you must find the video output name to which you should assing the new mode. Just type xrandr and investigate which one is it. In my case this is HDMI-1.

1. Generate new modeline using cvt:

$ cvt 1920 1080 59
# 1920x1080 58.94 Hz (CVT) hsync: 66.02 kHz; pclk: 169.00 MHz
Modeline "1920x1080_59.00"  169.00  1920 2040 2240 2560  1080 1083 1088 1120 -hsync +vsync
  • 1920 and 1080 are the horizontal and vertical resolution's values.
  • 59 is the value of the refresh rate.

2. Create the new mode:

xrandr --newmode 1920x1080_59.00  169.00  1920 2040 2240 2560  1080 1083 1088 1120 -hsync +vsync

3. Assign the new mode to the video output:

xrandr --addmode HDMI-1 1920x1080_59.00

4. Activate the new mode:

xrandr --output HDMI-1 --mode 1920x1080_59.00

If the above works and the problem disappear, you should find a proper way to add and set this mode at the system startup. Here are few references about that:

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I've no answer here, but some observation and confirmation of problem. If someone finds this text: please stick to ubuntu 17.10 if you have radeon rx 580 (may be 480 and vegas)

Got myself to very same situation with 18.04 (upgrade, then fresh install). Amd rx 580 here, kernel 4.15.0-20.

What did not help:

  • fresh install after upgrade
  • oibaf drivers
  • M-Bab custom kernel
  • 4.17-rc3 kernel from main line ppa.
  • amdgpu.dc=1 as boot parameter (/etc/default/grub)

Update: Apparently older kernel works. I've been tinkering with other distibutions and found that kernel 4.15.14 works for rx 580, you may want to try it from mainline ppa.

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  • Hi, try amdgpu.dc=0. It solves the problem. – LaoPiSai May 5 '18 at 1:57
  • Kernel 4.15 is no longer maintained by Linux Kernel developers. You can also try the 4.14 chain from the same mainline PPA. It is maintained for 5 or 6 years. I'm using 4.14.34 myself as 4.14.36 and 4.14.37had symbolic link bugs which prevented installing. – WinEunuuchs2Unix May 12 '18 at 22:31

I faced a similar problem,I wasn't able to log in with the graphical mode at all, I solved it by :
1- enter to tty mode (ctrl+alt+f5, en my case)
2- adding open grafic Drivers (https://launchpad.net/~oibaf/+archive/ubuntu/graphics-drivers):

      sudo add-apt-repository ppa:oibaf/graphics-drivers
      sudo apt-get update

3- reboot
4- enter into tty mode again

 sudo apt update && sudo apt full-upgrade
6- reboot and it works fine!!
hope it helps.

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  • Thank you very much @Hassan for sharing the instructions. In my case I cannot get into the tty. Just to make sure, where do you ctrl+alt+f5? Does your computer have a fn key? – Delosari Jul 14 '18 at 23:01
  • This fixed my flickering, thanks! – Kenivia May 1 at 23:16

Turn off the automatic brightness control to fix this.

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Just got 4.19-rc1 kernel installed and flickering is completly gone, no need to restart PC no other magic - it works out of the box.

I'm using Arch now, but believe ubuntu's mainline kernel going to provide same experience. http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.19-rc1/

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I had the same issue with my RX580 (Kubuntu 18.04, Plasma 5). The flickering only started when the GPU got higher load (playing the Witcher 3 in my case).

First I installed the 4.19 kernel (which has amdgpu.dc=1 by default).

That alone didn't seem to help but maybe contributes to the fix.

Than, I set the screen refresh rate to 59.xx hz with the KDE monitor settings GUI.

After this, the problem seems to be fixed.

In my case the flickering started when I manually switched screen resolution with xrandr (without an explicit refresh rate setting), so maybe the refresh rate was misconfigured by those commands and only the refresh rate needed to be fixed.

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I have RX460 and the same problem. Changing kernels or installing amdgpu-pro drivers didn't solve the issue.

The only way I could get rid of the flicker is to set the refresh rate from 74.9 to 60Hz.

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Had the same issue myself. It might have been the kernel, but what fixed it nicely for me was leaving all the defaults on (including refresh rate) and going into my monitors settings and disabling FreeSync.

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Installing liquorix kernel 5.2.0-27 on debian 10.1 solves the screen flickering at 75hz ,for my rx550

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