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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 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 :)

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up vote 0 down vote accepted

In this case still try to use the newest AMD proprietary driver from this step-by-step guide:

There is also described how to solve problems with suspend/hibernation.

To increase your performance after installing the propriatry driver, do follwing:

Install via Ubuntu Software Center Compiz Settings Manager by searching ccsm. Start Compiz Settings Manager via Dash - go to the button OpenGL and disable Sync VBlank. Do NOT modify other settings!!

Finally, you'll still have a problem with the flash performance when you are using the proprietary driver. To solve this, open a terminal window and type (or simple copy&paste):

sudo mkdir /etc/adobe && echo "OverrideGPUValidation=true"|sudo tee /etc/adobe/mms.cfg

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