gentoo-legion/docs/hybrid-gpu.md

Hybrid GPU Configuration

Guide for configuring AMD + NVIDIA hybrid graphics on Legion laptops with Hyprland.

Hardware Topology

On Legion laptops with hybrid graphics:

• AMD iGPU (card1): Drives the laptop display (eDP-2)
• NVIDIA dGPU (card0): Drives external displays (DP-1, DP-2 via USB-C)

This is hardware-wired and cannot be changed via software.

BIOS Configuration

Critical: Set GPU mode to Hybrid/Dynamic (not Discrete).

Discrete mode may cause:

• Lower resolution options on laptop display
• Display detection issues
• Power management problems

NVIDIA Driver Setup

Install Drivers

emerge x11-drivers/nvidia-drivers

Blacklist Nouveau

echo "blacklist nouveau" > /etc/modprobe.d/blacklist-nouveau.conf
echo "options nouveau modeset=0" >> /etc/modprobe.d/blacklist-nouveau.conf

Enable DRM

echo "options nvidia_drm modeset=1 fbdev=1" > /etc/modprobe.d/nvidia.conf

GRUB Configuration

Add to /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="nvidia_drm.modeset=1 acpi_backlight=native"

Regenerate:

grub-mkconfig -o /boot/grub/grub.cfg

Dracut Configuration

Create /etc/dracut.conf.d/nvidia.conf:

add_drivers+=" nvidia nvidia_modeset nvidia_uvm nvidia_drm "
force_drivers+=" nvidia nvidia_modeset nvidia_uvm nvidia_drm "

Rebuild initramfs:

emerge --config sys-kernel/gentoo-kernel

Hyprland Configuration

GPU Auto-Detection

Hyprland should auto-detect GPUs. Do NOT set these variables in your config:

# Leave these commented out for auto-detection
# env = AQ_DRM_DEVICES,/dev/dri/card0:/dev/dri/card1
# env = AQ_MGPU_NO_EXPLICIT,1

If auto-detection fails, try explicit order as fallback:

env = AQ_DRM_DEVICES,/dev/dri/card1:/dev/dri/card0
env = AQ_MGPU_NO_EXPLICIT,1

Monitor Configuration

Example triple-monitor layout:

# Left external | Center laptop | Right external
monitor=DP-1, 1920x1080@60, 0x0, 1
monitor=eDP-2, 1920x1080@60, 1920x0, 1
monitor=DP-2, 1920x1080@60, 3840x0, 1

Use hyprctl monitors to get your monitor names.

Cursor Fix (Multi-GPU)

Disable hardware cursors to prevent duplicate/missing cursor issues:

In ~/.config/hypr/configs/SystemSettings.conf:

cursor {
    no_hardware_cursors = 2
    default_monitor = eDP-2
}

Workspace Assignment

Assign workspaces to specific monitors:

workspace = 1, monitor:eDP-2, default:true
workspace = 2, monitor:DP-1, default:true
workspace = 3, monitor:DP-2, default:true

Gaming

Games automatically use the NVIDIA GPU in hybrid mode. No prime-run needed for most cases.

If a game isn't using the NVIDIA GPU:

prime-run <application>

Or set environment variables:

__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia <application>

Backlight Control

The laptop backlight is controlled by the AMD iGPU. If brightness controls don't work:

1. Check available backlight devices:

   ls /sys/class/backlight/
   

2. Use the correct device in brightness scripts (usually amdgpu_bl1 for Legion).

3. GRUB setting helps:

   GRUB_CMDLINE_LINUX_DEFAULT="... acpi_backlight=native"
   

Troubleshooting

Pink/Artifacts on External Monitors

1. Ensure BIOS is set to Hybrid/Dynamic mode
2. Try letting Hyprland auto-detect GPUs (comment out AQ_* variables)
3. If auto-detect fails, try explicit GPU order

External Monitors Not Detected

1. Check connections (USB-C to DisplayPort)
2. Verify NVIDIA driver is loaded: lsmod | grep nvidia
3. Check Xorg/Wayland logs for errors

Performance Issues

1. Verify NVIDIA persistence daemon is running
2. Check power profile: powerprofilesctl get
3. Monitor GPU usage: nvidia-smi

Screen Tearing

Ensure NVIDIA DRM is enabled:

cat /sys/module/nvidia_drm/parameters/modeset
# Should return: Y