I'm using the default drivers (Mesa?) installed by default in Ubuntu 11.10. The problem is that in sometimes the monitor image is unstable and when the system turn on the screensaver, the monitor display "no signal detected" and I have to reboot the machine pressing the reset button.
I tried to update the drivers with the ppa http://ppa.launchpad.net/ubuntu-x-swat/x-updates/ubuntu but the problem persists.
I'm using Ubuntu 11.10 and my video device is an AMD HD4200. I don't want to install the propietary drivers cause the bad performance (I had to reinstall Ubuntu 11.10 because that)
¿any solution? thanks in advance and sorry for my bad English :)