I've been trying to get dual external monitors working on a Dell Studio 1458 / Ubuntu 10.04 laptop with an ATI Radeon HD 5450 to no avail. The laptop has two video outputs: HDMI and VGA. Some of my notes:
* I've tried this using both Catalyst 10.4 and 10.5
* I'd like to run this in multi-display desktop mode
* One monitor is direct HDMI to DVI, the other is VGA to DVI
* I can get a laptop + HDMI or laptop + VGA configuration working, but not an HDMI + VGA configuration
* If I try to enable HDMI + VGA and disable the laptop monitor, only the HDMI connection displays anything
Is it possible to run in an HDMI + VGA configuration (with the laptop monitor disabled)? Does anyone have any tips on other things to try? If it's not possible with the hardware, are there any other recommendations?
I had been using the ATI Catalyst Control Center UI. I actually hadn't heard of xrandr until yesterday. Sure enough, setting up the dual-monitor configuration through xrandr worked flawlessly!
Is xrandr the recommended way of configuring the displays instead of the Catalyst UI or aticonfig? It seems that the Catalyst UI works by changing xorg.conf and requiring restarts, whereas xrandr doesn't. Also, the "Monitors" preference app in Ubuntu never seemed to worked very well for me.