Fixing not working backlight controls on Ubuntu 10.04 Lucid @ HP Compaq 615 notebook

Ubuntu generally works like a charm on the HP Compaq 615 low-budget notebook. I own one since ~1 year, using the proprietary ATI Radeon driver provided by Ubuntu's Hardware Driver Assistant for the on-board Radeon HD 3200 graphic card. Never had any problems with it.

However, since Ubuntu 10.04 Lucid the display background lighting controls/buttons do not work properly with the proprietary driver recommended by Ubuntu's Hardware Driver Assistant (System→Administration→Hardware Drivers). To fix this problem, simply upgrade to the newest ATI Radeon Driver provided by AMD:

1. Deactivate the currently used proprietary ATI Radeon driver (System→Administration→Hardware Drivers) and reboot afterwards to be on the safe side.
2. Download the newest driver from http://support.amd.com/: Download graphics drivers → Integrated Motherboard Graphics → Radeon HD 3xxx Series → Radeon HD 3200 Series → Linux x86_64 (for 64bit systems) or Linux x86 (for 32bit systems)
3. Open a terminal, make the downloaded ati-driver-installer-<version>.run file executable and start it with superuser privileges:

   chmod a+rx /path/to/ati-driver-installer-<version>.run
   sudo /path/to/ati-sriver-installer-<version>.run

4. An installation wizard will start → Install Driver → Automatic. After rebooting your system, everything should be fine. You may delete the downloaded file now.

Please note: you have to do this again after you are installing a kernel update. If the new driver is not compatible to your kernel, you can always switch back to the one shipped with Ubuntu.

Update 2010-11-03: backlight controls are working out of the box on Ubuntu 10.10 Maverick and the proprietary ATI driver provided by Ubuntu's additional driver wizard.