optimus-manager

This Linux program provides a solution for GPU switching on Optimus laptops (a.k.a laptops with dual Nvidia/Intel GPUs).

Obviously this is unofficial, I am not affiliated with Nvidia in any way.

Only Archlinux (plus derivatives like Manjaro) is supported for now. Only Xorg sessions are supported (no Wayland).

Supported display managers are : SDDM, LightDM, GDM. The program might still work with others but you have to configure them manually (see this section).

The "why"

On Windows, the Optimus technology works by dynamically offloading rendering to the Nvidia GPU when running 3D-intensive applications, while the desktop session itself runs on the Intel GPU.

However, on Linux, the Nvidia driver does not provide such offloading capabilities (yet), which makes it difficult to use the full potential of your machine while keeping a reasonable battery life.

Currently, if you have Linux installed on an Optimus laptop, there are three methods to use your Nvidia GPU :

• Run your whole X session on the Intel GPU and use Bumblebee to offload rendering to the Nvidia GPU. While this mimic the behavior of Optimus on Windows, this is an unofficial, hacky solution with three major drawbacks : 1. a noticeable performance hit (because Bumblebee has to use your CPU to copy frames over to the display) 2. no support for Vulkan (therefore, it is incompatible with DXVK and any native game using Vulkan, like Shadow of the Tomb Raider for instance) 3. you will be unable to use any video output (like HDMI ports) connected to the Nvidia GPU, unless you have the open-source nouveau driver loaded to this GPU at the same time.

• Use nvidia-xrun to have the Nvidia GPU run on its own X server in another virtual terminal. You have to keep two X servers running at the same time, which can be detrimental to performance. Also, you do not have acess to your normal desktop environment while in the virtual terminal of the Nvidia GPU, and in my own experience, the nvidia driver is prone to crashing when switching between virtual terminals.

• Run your whole X session on the Nvidia GPU and disable rendering on the Intel GPU. This allows you to run your applications at full performance, with Vulkan support, and with access to all video outputs. However, since your power-hungry Nvidia GPU is turned on at all times, it has a massive impact on your battery life. This method is often called Nvidia PRIME, although technically PRIME is just the technology that allows your Nvidia GPU to send its frames to the built-in display of your laptop via the Intel GPU.

An acceptable middle ground could be to use the third method on demand : switching the X session to the Nvidia GPU when you need extra rendering power, and then switching it back to Intel when you are done, to save battery life.

Unfortunately the X server configuration is set-up in a permanent manner with configuration files, which makes switching a hassle because you have to rewrite those files every time you want to switch GPUs. You also have to restart the X server for those changes to be taken into account.

This is what this tool does for you : it dynamically writes the X configuration at boot time, rewrites it every time you need to switch GPUs, and also loads the appropriate kernel modules to make sure your GPUs are properly turned on/off.

Note that this is nothing new : Ubuntu has been using that method for years with their prime-select script.

In practice, here is what happens when switching to the Intel GPU (for example) :

1. Your login manager is automatically stopped, which also stops the X server (warning : this closes all opened applications)
2. The Nvidia modules are unloaded and nouveau is loaded instead to switch off the card (this can also be done with bbswitch if nouveau does not work)
3. The configuration for X and your login manager is updated (note that the configuration is saved to dedicated files, this will not overwrite any of your own configuration files)
4. The login manager is restarted.

I am well-aware this is still a hacky solution. I will happily deprecate this tool the day Nvidia implements proper GPU offloading in their Linux driver.

Installation

You can use this AUR package : optimus-manager

Then, enable the daemon :

$ sudo systemctl enable optimus-manager.service

Then, reboot (it is necessary for the new Systemd configuration to take effect).

IMPORTANT : make sure you do not have any configuration file conflicting with the ones autogenerated by optimus-manager. In particular, remove everything related to displays or GPUs in /etc/X11/xorg.conf and /etc/X11/xorg.conf.d/ (and also in /etc/X11/mhwd.d/ for Manjaro users). Also, avoid running nvidia-xconfig or using the Save to X Configuration file in the Nvidia control panel. If you need to apply specific options to your Xorg config, see the Configuration section.

Also, if you have bumblebee installed on your system, uninstall it or at least make sure the bumblebeed service is disabled. Finally, make sure the bbswitch module is not loaded at boot time (check /etc/modules-load.d/).

Uninstallation

If you do not want to use optimus-manager anymore, you need to run optimus-manager --cleanup to clear any leftover autogrenerated configuration file, then uninstall the program. Just disabling the daemon is not enough because the Sytemd scripts will still be executed.

Usage

Make sure the SystemD service optimus-manager.service is running, then run

optimus-manager --switch nvidia

to switch to the Nvidia GPU, and

optimus-manager --switch intel

to switch to the Intel GPU.

(you can also use optimus-manager --switch auto to automatically switch to the other mode)

WARNING : Switching GPUs automatically restarts your display manager, so make sure you save your work and close all your applications before doing so.

You can setup autologin in your display manager so that you do not have to re-enter your password every time.

You can also specify which GPU you want to be used by default when the system boots :

optimus-manager --set-startup MODE

Where MODE can be intel, nvidia, or nvidia_once. The last one is a special mode which makes your system use the Nvidia GPU at boot, but for one boot only. After that it reverts to intel mode. This can be useful to test your Nvidia configuration and make sure you do not end up with an unusable X server.

System Tray Icon

optimus-manager includes a system tray icon that makes it easy to switch GPUs. It should work on most desktop environments.

To make the tray icon automatically launch with your DE, it is usually enough to do:

ln -s /usr/share/applications/optimus-manager-systray.desktop ~/.config/autostart/optimus-manager-systray.desktop

Someone also made a Gnome Shell extension for this program, you can find it here : optimus-manager-argos.

Configuration

The default configuration file can be found at /usr/share/optimus-manager.conf. Please do not edit this file ; instead, edit the config file at /etc/optimus-manager/optimus-manager.conf (create it if it does not exist).

(Note : the user configuration file used to be at /etc/optimus-manager.conf. This path is now deprecated. It still works for now but will be ignored in the future.)

Any parameter not specified in your config file will take value from the default file. Remember to include the section headers of the options you override.

Please refer to the comments in the default config file for descriptions of the available parameters. In particular, it is possible to set common Xorg options like DRI version or triple buffering, as well as some kernel module loading options.

You can also add your own Xorg options in /etc/optimus-manager/xorg-intel.conf and /etc/optimus-manager/xorg-nvidia.conf. Anything you put in those files will be written to the "Device" section of the auto-generated Xorg configuration file corresponding to their respective GPU mode.

FAQ / Troubleshooting

General troubleshooting advice : you can view the logs of the optimus-manager daemon by running journalctl -u optimus-manager.service, but the most important log is the one from your display manager : journalctl -u display-manager.service. Please include both if you have to open a GitHub issue. Add -b0 if you want to see the logs for the current boot, -b-1 for the previous boot, and add --no-pager if you need to copy-paste the whole log.

The Arch wiki can be a great resource for troubleshooting. Check the following pages : NVIDIA, NVDIA Optimus, Bumblebee (even if optimus-manager does not use Bumblebee, some advices related to power switching can still be applicable)

How can I check which GPU my X session is running on ?

Run optimus-manager --print-mode. Alternatively, you can run glxinfo | grep "server glx vendor string". You will see Nvidia corporation if you are running on Nvidia, and SGI otherwise.

When I switch GPUs, my system completely locks up (I cannot even switch to a TTY with Ctrl+Alt+Fx)

It is very likely your laptop is plagued by one of the numerous ACPI issues associated with Optimus laptops on Linux, and caused by manufacturers having their own implementations. The symptoms are often similar : a complete system lockup if you try to run any program that uses the Nvidia GPU while it is powered off. Unfortunately there is no universal fix, but the solution often involves adding a kernel parameter to your boot options. You can find more information on this GitHub issue, where people have been reporting solutions for specific laptop models. Check this Arch Wiki page to learn how to set a kernel parameter at boot.

You can also try changing the power switching backend in the configuration file (section [optimus], parameter switching).

GPU switching works but my system locks up if I am in Intel mode and start any of the following programs : VLC, lspci, anything that polls the PCI devices

This is due to ACPI problems, see the previous question.

I think my Nvidia GPU stays powered on even in Intel mode (my battery drains too fast)

Maybe there is a problem with nouveau not handling power switching properly. Check dmesg for errors related to nouveau or PCI power management. You can also try switching the power switching backend to bbswitch (option switching, Section [optimus])

My display manager is not SDDM, LightDM nor SDDM

You must configure it manually so that it executes the script /usr/bin/optimus-manager_Xsetup on startup. The X server may still work without that step but your login manager will show a black screen on the built-in monitor instead of the login window. You can set up autologin to avoid that.

The display manager stops but does not restart (a.k.a I am stuck in TTY mode)

This is generally a problem with the X server not restarting. Refer to the next question.

When I try to switch GPUs, I end up with a black screen (or a black screen with only a blinking cursor)

First, make sure your system is not completely locked up and you can still switch between TTYs with Ctrl+Alt+F1,F2,etc. If you cannot, refer to this question.

If you can, it generally means that the X server failed to restart. In addition to the optimus-manager logs, you can check the Xorg logs at /var/log/Xorg.0.log for more information.

Some fixes you can try :

• Setting the power switching backend to bbswitch in the configuration file (section [optimus], parameter switching)
• Setting modeset to no in the [intel] and [nvidia] sections
• Changing the DRI versions from 3 to 2

If that does not fix your problem and you have to open a GitHub issue, please attach the Xorg log in addition to the optimus-manager daemon log and the display manager log.

GPU switching works but I cannot run any 3D application in Intel mode (they fail to launch with some error message)

Check if the nvidia module is still loaded in Intel mode. That should not happen, but if it is the case, then logout, stop the display manager manually, unload all Nvidia modules (nvidia_drm, nvidia_modeset, nvidia-uvm, and nvidia, in that order) and restart the display manager.

Consider opening a GitHub issue about this, with logs attached.

After switching GPUs, I experience poor CPU performance or heavy stuttering, or my external video outputs do not work

If the problem occurs after switching to Nvidia, try setting modeset to no in the [nvidia] section of the configuration file.

If the problem occurs after switching to Intel, try setting modeset to no in the [intel] section of the configuration file, or you can also try disabling nouveau by setting the switching option in the [optimus] section to bbswitch. Note that those two fixes may prevent you from using your video outputs (such as HDMI) in Intel mode.

I do not want optimus-manager to stop/restart my display manager

You can disable control of the login manager by setting the option login_manager_control to no in the section [optimus] of the config file. With that configuration, the GPU switch will happen the next time you restart the display manager service after calling optimus-manager --switch.

I do not use a display manager (I use startx or xinit)

First, you have to add the line /usr/bin/optimus-manager_Xsetup to your .xinitrc so that this script is executed when X starts. This may be necessary to set up PRIME.

Switching GPUs is also a little different in that case. First, the X server must not be running while switching (because the rendering kernel modules need to be unloaded), so you have do it from a TTY for example. Call optimus-manager --switch, then /usr/bin/optimus-manager-setup --setup-start, then start the X server. After you close the X server, it is recommended you also do /usr/bin/optimus-manager-setup --setup-stop to remove leftover configuration files.

When I switch to Nvidia, the built-in screen of the laptop stays black but I can still input my password or use monitors plugged to a video output

It seems that PRIME is not properly configured. Please open a GitHub issue with logs attached, and include as much details about your login manager as you can.

Could this tool work on distributions other than Arch or its derivatives ?

Maybe. It will not work on Ubuntu because Canonical has its own tool to deal with Optimus (prime-select). If you are on Ubuntu you should be using that.

It will not work on the default install of Fedora because it uses Wayland (it might work in Xorg mode though).

I do not know enough about the specificities of other distributions to port this tool to them. Feel free to help though :)

Credit

The Intel and Nvidia logos are from the FlatWoken project created by Alessandro Roncone.