bbswitchd

Daemon for managing discrete NVIDIA GPU power state on Optimus laptops.

Useful for pre-Turing GPU generations without dynamic power management features, allows to fully benefit from NVIDIA PRIME Render Offload technology without need to keep graphics adapter turned on all the time.

For Turing generation cards with Intel Coffee Lake or above CPUs as well as some Ryzen CPUs like the 5800H, it is possible to fully power down the GPU when not in use automatically without user interaction: see NVIDIA documentation.

Uses bbswitch kernel module to switch video adapter power state (ON or OFF).

Installation

Requirements

First you have to install kmod library and meson build system. If you need SELinux module, selinux-policy developent package has to be installed as well.

For Fedora:

$ sudo dnf install kmod-devel meson # selinux-policy-devel

For Ubuntu:

$ sudo apt-get install libkmod-dev meson # selinux-policy-dev

Building from source

Then build the daemon (in build subdirectory). If you need SELinux module (which is usually required for RHEL-based distributions such as Fedora), add -Dselinux=enabled option to meson build command:

$ meson build # -Dselinux=enabled
$ meson compile -C build

To install a daemon on your system:

$ meson install -C build

If you have built SELinux module, you need to load it after installation:

$ sudo semodule -n -i /usr/share/selinux/packages/bbswitchd.pp
$ sudo /usr/sbin/load_policy
$ sudo restorecon -R /usr/sbin/bbswitchd

Usage

First create bbswitchd group and add yourself to it:

$ sudo groupadd -r bbswitchd
$ sudo gpasswd -a $(whoami) bbswitchd

Then enable and start the socket:

$ sudo systemctl enable bbswitchd.socket
$ sudo systemctl start bbswitchd.socket

After re-login you should be able to use bbswitch utility from your regular user:

$ bbswitch
bbswitch
Usage: bbswitch on | off
$ bbswitch on  # Turn discrete GPU on
$ bbswitch off # Turn discrete GPU off

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

This software is distributed under GNU GPL v3. See LICENSE file for more information.