#98   Hybrid Graphic Cards and MUX

Hybrid graphics systems combine an integrated GPU (iGPU) built into the CPU, with a discrete GPU (dGPU), a separate powerful card, typically in laptops or specialized some hardware. The iGPU handles low-power tasks and often drives display outputs, while the dGPU manages compute-intensive workloads; display routing determines which GPU connects to screens and ports, affecting performance and power use. MUX (Multiplexer) is a switching mechanism between integrated and dedicated graphics processors on laptops and desktop systems. Linux support varies. MUX Availability BIOS Check. Restart your machine then enter BIOS. Search for Graphics, MUX, Optimus, dGPU. GPU Listing List GPU lspci | grep VGA Example output of dual system 00:02.0 VGA compatible controller: Intel Corporation HD Graphics 630 01:00.0 VGA compatible controller: NVIDIA Corporation GP107M [GeForce GTX 1050] Alternative GPU listing glxinfo | grep "OpenGL renderer" Example output AMD Radeon RX 6700 (NAVI23, DRM 3.XX, 5.XX.XX) AMD Radeon Vega 10 (VEGA10, DRM 3.XX, 5.XX.XX) Display Route Set: xrandr --setprovideroutputsource 1 0 (dGPU provider 1 to iGPU 0), then xrandr --output HDMI-1 --provider 1. PRIME It is a technology used to manage hybrid graphics systems with Nvidia cards on recent desktops and laptops. Install # debian sudo apt install nvidia-prime # arch sudo pacman nvidia-prime Switch to dGPU sudo prime-select nvidia Switch to iGPU sudo prime-select intel AMD Switcheroo It leverages the open-source AMD kernel drivers to provide seamless GPU switching. It is also called VGASWITCHEROO. List GPUs cat /sys/kernel/debug/vgaswitcheroo/switch Example output: 0:IGD:+:Int:0 0000:00:02.0 1:DIS: :Dis:0 0000:0c:00.0 The first line 0:IGD:+: means GPU 0 (Integrated Graphics Device) is currently active; The second line: 1:DIS: : means GPU 1 (Discrete) is inactive. The format is ID:NAME:State:Type:PCI_ID. View Current Switch Status cat /sys/kernel/debug/vgaswitcheroo/switch Switch to Discrete GPU echo "DIGD" | sudo tee /sys/kernel/debug/vgaswitcheroo/switch Switch to Integrated GPU echo "IGD" | sudo tee /sys/kernel/debug/vgaswitcheroo/switch Disable Discrete GPU (Power Off) echo "OFF" | sudo tee /sys/bus/pci/devices/0000:0c:00.0/power/control Replace 0000:0c:00.0 with your discrete GPU's PCI ID from lspci output. Enable Discrete GPU (Power On) echo "ON" | sudo tee /sys/bus/pci/devices/0000:0c:00.0/power/control Check Current Power State cat /sys/bus/pci/devices/0000:0c:00.0/power/control Output is auto, on, or off. Display Server After switching the active GPU, you need to restart your display server. Simply logout and log back in.

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