Ubuntu 12.04 dual monitors stay mirrored

Question

I just installed Ubuntu 12.04 and I'm having some trouble getting my two monitors working properly. I have one 24" Samsung and one 23" Acer, both running 1920x1080. My video card is a ATi HD5870.

By default the monitors are set to mirror but I want it to extend across both screens. I tried to uncheck the mirror option in Displays, but it complained that 3840x1080 was too big.

I installed the ATi propriety drivers and went into Catalyst Control Center and set the displays to be extended like I want. I was prompted to reboot, so I did, and nothing changed - the displays are still mirrored.

Solution

It's not the same question but this answer did the trick for me

Comments

[Boris]

I think that you just need to do step 4 of this askubuntu.com/a/128862/32413

[Boris]

I think that you should point the response in your link and not the question to avoid misunderstanding

[Ron Smith]

Good call @Boris, I updated the link.