Since Linux 3.13, Radeon power management is enabled by default. This is great if you have a supported card, but if you don’t, you may encounter issues such as overheating and overeager cooling fans. If you fall into the latter category, you can use these instructions to disable the new power management features.
Disable Radeon power management
- Add the parameter radeon.runpm=0 to the Linux kernel boot parameters by editing /etc/default/grub. This is accomplished by appending the parameter to the value of GRUB_CMDLINE_LINUX_DEFAULT. After doing so, that line in my grub file looks like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.runpm=0"
- Reboot your computer.
Manually control the GPU
You can now manually manage the power of your graphics card, by using vgaswitcheroo or similar.
Personally, I completely disable my discrete graphics card under Linux by adding the following line to /etc/rc.local:
echo OFF > /sys/kernel/debug/vgaswitcheroo/switch
You can verify that the card is off by running the
sensors command. When my discrete GPU is switched off,
sensors reports the temperature as 511°C:
radeon-pci-0100 Adapter: PCI adapter temp1: +511.0°C (crit = +120.0°C, hyst = +90.0°C)
These pages were useful to me while researching how to disable Radeon power management: