/etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="radeon.runpm=0"
sudo update-grub
Voir https://bbs.archlinux.org/viewtopic.php?id=177254
/etc/modprobe.d/boot_radeon.conf
options radeon dpm=1 options radeon audio=1 options radeon runpm=0
sudo update-initramfs -k all -u
cat /sys/kernel/debug/vgaswitcheroo/switch echo OFF > /sys/kernel/debug/vgaswitcheroo/switch echo DIS > /sys/kernel/debug/vgaswitcheroo/switch