This simple tutorial will explain how to turn off discrete card on a Ubuntu laptop with two graphic cards. Discrete graphic card takes up more energy and the processor usage. If you seldom use the discrete card, follow the steps to turn it off.
1. On Ubuntu, hit Ctrl+Alt+T to launch a terminal window. Copy and paste this command in terminal, and hit enter to switch to hybrid graphics:
echo IGD > /sys/kernel/debug/vgaswitcheroo/switch
2. Then execute this command to temporarily turn off discrete card:
echo OFF > /sys/kernel/debug/vgaswitcheroo/switch
If the indicator lamp runout, follow step 3 to turn off discrete card on boot.
3. Edit /etc/rc.local file with your favorite editor:
sudo gedit /etc/rc.local
Copy the two commands from step 1 & 2, and paste them before exit 0 . Make it looks like:
Check the result by this command:
It should output something like this: