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Whenever I restart the X session, either from a suspension or a screen lock, the screen is a mesh of lines where I can not even see the mouse. To make it work I switch to another session (say, Ctrl+Alt+F1) and then go back to the X session (Ctrl+Alt+F7). After a few seconds where nothing responds to the mouse the session becomes active again and all fine. This workaround has allowed me to keep working but it's not ideal. A permanent solution to this would be great.

I have an ATI Radeon HD 8600M and I'm using Xubuntu 14.04, with the ATI drivers (fglrx). If I use open-source drivers (X.org) the problem dissapears. However I'm not happy with this solution because I need propietary drivers to run some Matlab functionalities and other applications.

Another interesting info is that when I use two screens (laptop + external Dell monitor via HDMI) the problem only affects the laptop screen.

So I have the weird combination of, yes, it is the ATI driver, but only for the laptop screen....what could it be?

2 Answers 2

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I had the same problem as you mate. I also have ATI Radeon 8600M on my Dell laptop. I came up with two workarounds for this problem that I will describe, so you do not have to bang your head.

I know what I am going to propose you is not direct solution for the problem. It is the best workaround that I have found so far from my experience. I will be very happy if someone manages to solve the problem the proper way.

I have searched all over the internet for a proper solution, but I could not find one.

I have discovered that the source of the problem is deep into the LightDM locker and the fglrx drivers. There is some conflict that I could not tarce down and did not find any solution. Evrytime I close the Lid of my laptop and it suspend, after I open it up I see either black screen or the system freezes completely or my screen showed only color lines.

First soltuion that I have tried and it worked was to remove LightDM and replace it with xscreensaver. And it worked - no more black screens or freezes after suspend.

To remove light-locker and install xscreensaver, execute this in terminal:

sudo apt-get purge light-locker light-locker-settings
sudo apt-get install xscreensaver

But for me xscreensaver looks very ugly, so finally I have uninstalled Xubuntu and installed Ubuntu 14.10. I have no problems with unity so far.

The other solution is to remove fglrx, and use xorg opengl drivers. I found that if I am using this driver the problem does not occurs. But I needed fglrx to run wine games so that was not solution for me ...

If you can not unsintall fglrx can you open the terminal and type:

sudo apt-get purge fglrx*

Paste any error output in you question.

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  • Is removing fglrx secure? How do I install the alternative? Will I not crash my GUI- X session?
    – user308164
    Apr 11, 2015 at 18:13
  • By removing fglrx you will fallback to the xorg open source drivers for AMD. You can see this through Additional drivers menu. Don't worry it is safe.
    – Sh1d0w
    Apr 11, 2015 at 19:25
  • Sorry to insist but what about this answer? There it says you have to reinstall xorg.
    – user308164
    Apr 12, 2015 at 8:23
  • Yes you can do it his way if you prefer. The same will happen if you switch form fglrx to xorg drivers from "Additional drivers" window. Let me know if you need further information or help.
    – Sh1d0w
    Apr 12, 2015 at 8:27
  • Ok, I tried the full solution and didn't work. After restarting, a message drm: radeon_acpi_init Error: Cannot find a backlight controller appears and then logs into a black screen where I can only see the mouse. I enter my password and enter into my session but black screen. Can play around with mouse and get some effects but screen is messy. I had to reinstall fglrx within tty1, reboot and now back to before state. Also, this looks daunting to me so don't know how to proceed.
    – user308164
    Apr 12, 2015 at 19:23
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This problem was solved when upgrading to 16.04. Screen has no single glitch. Suspend works fine. The open-source radeon driver works flawlessly! No need to miss fglrx.

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