@John Winterton - You are half right. CPU overhead is higher with the open-source radeon driver than with the closed-source Catalyst (fglrx) driver. However the ATI/AMD GPU is used as much more than just a presentation device - most of the 3D calculations and rendering (including parts of Ubuntu's Unity desktop) are done on the GPU. Most of the excess heat produced by the radeon driver compared to the fglrx driver is produced by the GPU. Although there is some basic power management in the radeon driver - see http://www.x.org/wiki/radeonBuildHowTo#radeon-KMS_power-management - not only does the dynpm method not work on some hardware, when it does both it and the profile method only reduce heat and increase battery life partially when compared to the fglrx driver.
That said, there is some work going on to reduce the CPU overhead of the radeon driver. Some improvements were made in Mesa 7.11 (used in Ubuntu 11.10) for both the r300g driver for old hardware up to and including the Radeon X1000 series GPUs and the r600g driver for newer hardware from Radeon HD2000 series and later. There was at least one improvement to the r600g driver in Mesa 9.0 (used in Ubuntu 12.10 "Quantal Quetzal") - see http://cgit.freedesktop.org/mesa/mesa/commit/?id=c76462b45f1e3a0aa2ee7971191e30e8a5f52015 - and already another in the development tree for the future Mesa 9.1 - see http://cgit.freedesktop.org/mesa/mesa/commit/?id=e73bf3b805de78299f1a652668ba4e6eab9bac94 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to fglrx-installer in Ubuntu. https://bugs.launchpad.net/bugs/1058040 Title: fglrx-installer not working with HD2000-4000 "legacy" cards in Quantal Status in Release Notes for Ubuntu: New Status in “fglrx-installer” package in Ubuntu: Confirmed Bug description: Following the AMD decision to change to a new driver support model for Radeon™ HD 4000, HD 3000 and HD 2000 series cards as per http://support.amd.com/us/gpudownload/linux/legacy/Pages/legacy- radeon_linux.aspx , fglrx-installer installs non-working drivers. I suggest the addition of an fglrx-legacy package to install the AMD legacy drivers for users with older cards or patch the current code base for use with these cards. Output for fglrx 9.00 [1]: # lspci|grep VGA 01:05.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RS780L [Radeon HD 3000] # modprobe fglrx FATAL: Error inserting fglrx (/lib/modules/3.5.0-15-generic/updates/dkms/fglrx.ko): No such device # dmesg|tail -n3 [ 6785.693869] [fglrx] Maximum main memory to use for locked dma buffers: 7132 MBytes. [ 6785.694089] [fglrx:firegl_init_device_list] *ERROR* No supported display adapters were found [ 6785.694091] [fglrx:firegl_init_module] *ERROR* firegl_init_devices failed # dpkg --list|grep fglrx ii fglrx 2:9.000-0ubuntu1 amd64 Video driver for the AMD graphics accelerators ii fglrx-amdcccle 2:9.000-0ubuntu1 amd64 Catalyst Control Center for the AMD graphics accelerators [1] https://bugs.launchpad.net/ubuntu/+source/fglrx-installer- updates/+bug/1032672/comments/34 !!!!!!!! WARNING !!!!!!! The following workaround has produced mixed results and left some users with temporarily broken systems. It is not recommended for production systems or novice users that are not comfortable with basic console/non-GUI recovery. USE AT OWN RISK. WORKAROUND: sudo add-apt-repository ppa:makson96/fglrx && sudo apt-get update && sudo apt-get -y upgrade && sudo apt-get -y install fglrx-legacy This workaround will downgrade X to 1.12 and install the AMD legacy fglrx 8.97 (Catalyst 12.6). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-release-notes/+bug/1058040/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
