Configure the X Server

To use NVIDIA's PRIME render offload support, configure the X server with an X screen using an integrated GPU with the xf86-video-modesetting X driver and a GPU screen using the nvidia X driver. The X server will normally automatically do this, assuming the system BIOS is configured to boot on the iGPU and NVIDIA GPU screens are enabled in /etc/X11/xorg.conf.d/nvidia.conf:

Section "ServerLayout"
  Identifier "layout"
  Option "AllowNVIDIAGPUScreens"
EndSection

If GPU screen creation was successful, the log file /var/log/Xorg.0.log should contain lines with "NVIDIA(G0)", and querying the RandR providers with xrandr --listproviders should display a provider named "NVIDIA-G0" (for "NVIDIA GPU screen 0"). For example:

Providers: number : 2
Provider 0: id: 0x221 cap: 0x9, Source Output, Sink Offload crtcs: 3 outputs: 6 associated providers: 0 name:modesetting
Provider 1: id: 0x1f8 cap: 0x0 crtcs: 0 outputs: 0 associated providers: 0 name:NVIDIA-G0

Configure Graphics Applications to Render Using the GPU Screen

To configure a graphics application to be offloaded to the NVIDIA GPU screen, set the environment variable __NV_PRIME_RENDER_OFFLOAD to 1. If the graphics application uses Vulkan or EGL, that should be all that is needed. If the graphics application uses GLX, then also set the environment variable __GLX_VENDOR_LIBRARY_NAME to nvidia, so that GLVND loads the NVIDIA GLX driver.

Examples:

NV_PRIME_RENDER_OFFLOAD=1 vkcube
__NV_PRIME_RENDER_OFFLOAD=1 GLX_VENDOR_LIBRARY_NAME=nvidia glxinfo | grep vendor

Finer-Grained Control of Vulkan

The NV_PRIME_RENDER_OFFLOAD environment variable causes the special Vulkan layer VK_LAYER_NV_optimus to be loaded. Vulkan applications use the Vulkan API to enumerate the GPUs in the system and select which GPU to use; most Vulkan applications will use the first GPU reported by Vulkan. The VK_LAYER_NV_optimus layer causes the GPUs to be sorted such that the NVIDIA GPUs are enumerated first. For finer-grained control, the VK_LAYER_NV_optimus layer looks at the VK_LAYER_NV_optimus environment variable. The value NVIDIA_only causes VK_LAYER_NV_optimus to only report NVIDIA GPUs to the Vulkan application. The value non_NVIDIA_only causes VK_LAYER_NV_optimus to only report non-NVIDIA GPUs to the Vulkan application.

Examples:

NV_PRIME_RENDER_OFFLOAD=1 VK_LAYER_NV_optimus=NVIDIA_only vkcube
NV_PRIME_RENDER_OFFLOAD=1 VK_LAYER_NV_optimus=non_NVIDIA_only vkcube

Finer-Grained Control of OpenGL

For OpenGL with either GLX or EGL, the environment variable NV_PRIME_RENDER_OFFLOAD_PROVIDER provides finer-grained control. While NV_PRIME_RENDER_OFFLOAD=1 tells GLX or EGL to use the first NVIDIA GPU screen, __NV_PRIME_RENDER_OFFLOAD_PROVIDER can use an RandR provider name to pick a specific NVIDIA GPU screen, using the NVIDIA GPU screen names reported by xrandr --listproviders.

Examples:

NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia glxgears
NV_PRIME_RENDER_OFFLOAD_PROVIDER=NVIDIA-G0 GLX_VENDOR_LIBRARY_NAME=nvidia glxgears
__NV_PRIME_RENDER_OFFLOAD=1 eglinfo
NV_PRIME_RENDER_OFFLOAD_PROVIDER=NVIDIA-G0 eglinfo

Troubleshooting

After starting the X server, verify that the xf86-video-modesetting X driver is using "glamoregl". The log file /var/log/Xorg.0.log should contain something like this:

[1272173.618] (II) Loading sub module "glamoregl"
[1272173.618] (II) LoadModule: "glamoregl"
[1272173.618] (II) Loading /usr/lib/xorg/modules/libglamoregl.so
[1272173.622] (II) Module glamoregl: vendor="X.Org Foundation"
[1272173.622] compiled for 1.20.4, module version = 1.0.1
[1272173.622] ABI class: X.Org ANSI C Emulation, version 0.4
[1272173.638] (II) modeset(0): glamor X acceleration enabled on Mesa DRI Intel(R) HD Graphics 630 (Kaby Lake GT2)
[1272173.638] (II) modeset(0): glamor initialized

If glamoregl could not be loaded, the X log may report something like:

[1271802.673] (II) Loading sub module "glamoregl"
[1271802.673] (II) LoadModule: "glamoregl"
[1271802.673] (WW) Warning, couldn't open module glamoregl
[1271802.673] (EE) modeset: Failed to load module "glamoregl" (module does not exist, 0)
[1271802.673] (EE) modeset(0): Failed to load glamor module.

in which case, consult your distribution's documentation for how to (re-)install the package containing glamoregl.

If the server didn't create a GPU screen automatically, ensure that the nvidia-drm kernel module is loaded. This should normally happen by default, but you can confirm by running lsmod | grep nvidia-drm to see if the kernel module is loaded. Run modprobe nvidia-drm to load it.

If automatic configuration does not work, it may be necessary to explicitly configure the iGPU and dGPU devices in xorg.conf:

Section "ServerLayout"
  Identifier "layout"
  Screen 0 "iGPU"
  Option "AllowNVIDIAGPUScreens"
EndSection

Section "Device"
  Identifier "iGPU"
  Driver "modesetting"
EndSection

Section "Screen"
  Identifier "iGPU"
  Device "iGPU"
EndSection

Section "Device"
  Identifier "dGPU"
  Driver "nvidia"
EndSection

See also : https://download.nvidia.com/XFree86/Linux-x86_64/435.17/README/primerenderoffload.html