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I have a lot of problems with the Ati propietary driver (fglrx).

I have an iMac (mid 2011) with a Radeon HD 6900M [1002:6720].

I did not have any problem under Ubuntu 12.04, but since I updated to 12.10, I get some annoying graphic corruption.

The worst one is that sometimes the screen does not update with the new information. It happens a lot when I change between tabs in Chrome or Sublime Text. It usually gets updated when I scroll the page.

Sometimes, when I type, I have to wait a little bit to view the new characters.

And I get trails when I move windows too (like a part of the window). After a while, the trail disappears.

I tried to install fglrx, fglrx-updates and the new beta driver downloaded from Ati (12.11 Beta 11/16/2012), with no luck. It happens the same with all of them.

I tried to mess with Compiz config, but it didn't fix anything.

The open source driver does not suffer this problem, but I need the performance of the propietary driver .

Do you have any clue?


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I have the exact same problem with the exact same graphics card on a different set of hardware (non-apple).

It appears to be related to unity in combination with lightDM. I installed KDM as a solution and let that one start unity.

I also noticed that the corruption disappears when you have autologin turned on. If you log out and back in again, it behaves normally.

Update: The problem appears when you login to fast (for example with autologin). So another workaround would be to changen /etc/lightdm/lightdm.conf and set the autologin-user-timeout to 1 or greater.

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