Super-Shift-G-Mint-Deck-Mode/README.md

Super Shift G - Mint Deck Mode

Version 13.00-mint

Turn a Linux Mint Cinnamon desktop into a Steam Deck-like gaming console with a single keybind. Press Super+Shift+G to enter Gaming Mode (Steam Big Picture in Gamescope), and use Steam's "Exit to Desktop" to return to Cinnamon.

Built for Linux Mint running Cinnamon on LightDM.

What It Does

This installer transforms your desktop into a dual-mode system:

• Desktop Mode - Your normal Cinnamon (X11) session
• Gaming Mode - Full-screen Steam Big Picture running inside Gamescope (the same compositor used by the Steam Deck), with automatic performance tuning, controller support, and external drive mounting

Switching between modes is seamless — LightDM handles session transitions, and all your network, audio, and peripherals carry over automatically.

Requirements

• OS: Linux Mint (Ubuntu-based, tested on Mint 22)
• Desktop: Cinnamon (X11)
• Display Manager: LightDM
• GPU: AMD (discrete or APU) or NVIDIA (discrete)
  • Intel-only systems are not supported
  • Intel iGPU + AMD/NVIDIA dGPU configurations work fine

Note

: This script is designed specifically for Linux Mint and its stack (Cinnamon, LightDM, NetworkManager, PipeWire). It uses apt for package management and builds Gamescope from source as a recent build is not available in Mint repos. It is not intended for Arch-based or Fedora-based distributions — see Super-Shift-S-Omarchy-Deck-Mode for Omarchy/Arch, or Super-Shift-G-Nobara-Deck-Mode for Nobara/Fedora.

Quick Start

git clone https://git.no-signal.uk/nosignal/Super-Shift-G-Mint-Deck-Mode.git
cd Super-Shift-G-Mint-Deck-Mode
chmod +x super_shift_g_mint.sh
./super_shift_g_mint.sh

The installer is fully interactive and will walk you through each step.

Usage

Action	Keybind
Enter Gaming Mode	Super + Shift + G
Return to Desktop	Steam > Power > Exit to Desktop

Command-Line Options

./super_shift_g_mint.sh              # Full installation
./super_shift_g_mint.sh --verify     # Verify installation only
./super_shift_g_mint.sh --version    # Show version
./super_shift_g_mint.sh --help       # Show help

What Gets Installed

Packages (via apt)

The installer checks for and offers to install:

Core Steam Dependencies

• steam-installer, gamescope (built from source), mangohud (built from source), gamemode
• Vulkan loaders and Mesa libraries (32-bit and 64-bit)
• Audio libraries (PipeWire / pulseaudio compatibility)
• Fonts (fonts-liberation)

GPU-Specific Drivers

• NVIDIA: proprietary driver packages, libnvidia-egl-wayland1, VA-API driver
• AMD: libvulkan1, mesa-vulkan-drivers, libva-mesa-driver

Build Dependencies (for Gamescope from source)

• Meson, ninja, CMake, libwayland-dev, libdrm-dev, and others

ChimeraOS Session Scripts

• Cloned from GitHub — provides the gamescope-session framework

Apt Resilience

• If a package install hits a broken dpkg state or mirror failure, the installer automatically cleans the cache, retries, and falls back through multiple Ubuntu mirrors before failing.

Files Created

Session Scripts

Path	Purpose
/usr/local/bin/switch-to-gaming	Switches from Cinnamon to Gaming Mode
/usr/local/bin/switch-to-desktop	Switches from Gaming Mode back to Cinnamon
/usr/local/bin/gamescope-session-nm-wrapper	Main session wrapper (performance mode, NM, drive mounting)
/usr/local/bin/gaming-session-switch	Helper to toggle LightDM session config between modes
/usr/local/bin/gaming-keybind-monitor	Python daemon monitoring keyboard in Gaming Mode
/usr/lib/os-session-select	Handler for Steam's "Exit to Desktop" button
/usr/local/lib/gamescope-nvidia/gamescope	NVIDIA wrapper adding --force-composition flag

NetworkManager Integration

Path	Purpose
/usr/local/bin/gamescope-nm-start	Ensures NetworkManager is active on gaming session entry
/usr/local/bin/gamescope-nm-stop	No-op on Mint (NetworkManager always runs) — kept for compatibility

External Drive Support

Path	Purpose
/usr/local/bin/steam-library-mount	Auto-detects and mounts drives with Steam libraries

Session & Display Manager

Path	Purpose
/usr/share/xsessions/gamescope-session-steam-nm.desktop	LightDM session entry for Gaming Mode

Permissions & Security

Path	Purpose
/etc/sudoers.d/gaming-session-switch	Passwordless sudo for session switching, NM, bluetooth
/etc/sudoers.d/gaming-mode-sysctl	Passwordless sudo for performance sysctl tuning
/etc/polkit-1/rules.d/50-gamescope-networkmanager.rules	Polkit rules for NM D-Bus access
/etc/polkit-1/rules.d/50-udisks-gaming.rules	Polkit rules for external drive mounting
/etc/udev/rules.d/99-gaming-performance.rules	Udev rules for CPU/GPU performance control
/etc/security/limits.d/99-gaming-memlock.conf	Memory lock limits (2GB) for gaming

Performance & Environment

Path	Purpose
/etc/environment.d/99-shader-cache.conf	Shader cache optimisation (12GB Mesa/DXVK cache)
/etc/environment.d/90-nvidia-gamescope.conf	NVIDIA Gamescope environment variables
/etc/pipewire/pipewire.conf.d/10-gaming-latency.conf	PipeWire low-latency audio config

User Config

Path	Purpose
~/.config/environment.d/gamescope-session-plus.conf	Gamescope session config (resolution, refresh rate, GPU)

How It Works

Session Switching Flow

Desktop Mode (Cinnamon)
    |
    +- Super+Shift+G pressed
    |   +- switch-to-gaming runs:
    |       +- Masks suspend targets (prevents sleep during switch)
    |       +- Updates LightDM config to gaming session
    |       +- Restarts LightDM -> boots into Gaming Mode
    |
Gaming Mode (Gamescope + Steam Big Picture)
    |
    +- On session start (gamescope-session-nm-wrapper):
    |   +- Enables performance mode (CPU governor, GPU tuning)
    |   +- Ensures NetworkManager is active (Mint never stops NM)
    |   +- Launches steam-library-mount (external drive detection)
    |   +- Starts gaming-keybind-monitor
    |   +- Launches gamescope-session-plus with Steam
    |
    +- Steam > Power > Exit to Desktop
    |   +- switch-to-desktop runs:
    |       +- Unmasks suspend targets
    |       +- Restores Bluetooth
    |       +- Shuts down Steam gracefully
    |       +- Kills gamescope (releases DRM master — critical for AMD)
    |       +- Updates LightDM config to Cinnamon session
    |       +- Restarts LightDM -> boots into Desktop Mode
    |
    +- On session cleanup (trap handler):
        +- Kills steam-library-mount and keybind-monitor
        +- Restores balanced power mode

Performance Mode

When Gaming Mode starts, the session wrapper automatically:

• Sets CPU governor to performance on all cores
• NVIDIA: Enables persistence mode, sets power limit to maximum, disables runtime suspend
• AMD: Sets GPU to high performance via power_dpm_force_performance_level
• Applies kernel sysctl tuning (scheduler, VM, inotify, network buffers)
• Sets power profile to performance (if power-profiles-daemon is available)

On exit, everything is restored to balanced/powersave defaults.

GPU Detection

The installer automatically detects your GPU configuration:

• AMD dGPU: Detected via PCI device names (Navi, RDNA, Vega discrete cards)
• AMD APU: Detected via integrated GPU codenames (Phoenix, Rembrandt, Van Gogh, etc.)
• NVIDIA: Detected via lspci, configures nvidia-drm.modeset=1 if missing
• Multi-GPU: Correctly identifies discrete vs integrated, selects dGPU for gaming

Monitor Detection

The installer scans DRM connectors on your gaming GPU to find connected displays. If multiple monitors are connected to the dGPU, you can choose which one to use for Gaming Mode. Resolution and refresh rate are auto-detected from EDID data.

External Drive Auto-Mount

The steam-library-mount daemon runs during Gaming Mode and:

1. Scans all connected drives for Steam library folders
2. Mounts drives containing steamapps/ directories via udisks2
3. Monitors udev for hot-plugged drives
4. Unmounts non-Steam drives to avoid clutter

Supports ext4, NTFS, btrfs, xfs, exfat, f2fs, and vfat filesystems.

Configuration

Config File

The installer reads from /etc/gaming-mode.conf (or ~/.gaming-mode.conf if it exists):

PERFORMANCE_MODE=enabled   # Set to "disabled" to skip performance tuning

Gamescope Session Config

After installation, you can edit ~/.config/environment.d/gamescope-session-plus.conf:

SCREEN_WIDTH=2560
SCREEN_HEIGHT=1440
CUSTOM_REFRESH_RATES=165
OUTPUT_CONNECTOR=DP-1
ADAPTIVE_SYNC=1            # AMD only
ENABLE_GAMESCOPE_HDR=1     # AMD only

NVIDIA note: Resolution is capped at 2560x1440 due to Gamescope limitations with NVIDIA GPUs.

Shader Cache

The installer configures a 12GB shader cache by default in /etc/environment.d/99-shader-cache.conf. This reduces stutter in games by caching compiled shaders. Values can be adjusted:

MESA_SHADER_CACHE_MAX_SIZE=12G
__GL_SHADER_DISK_CACHE_SIZE=12884901888
DXVK_STATE_CACHE=1

Key Differences from Other Versions

	Omarchy (Arch)	Nobara (Fedora)	Mint (Ubuntu)
Package manager	pacman / yay	dnf	apt
Desktop	Hyprland	KDE Plasma	Cinnamon (X11)
Display manager	SDDM	plasmalogin	LightDM
Networking	iwd	NetworkManager	NetworkManager (never stopped)
Gamescope	pacman package	Built from source	Built from source
MangoHud	pacman package	dnf package	Built from source
ChimeraOS session	AUR packages	Cloned from GitHub	Cloned from GitHub
Gaming keybind	Super+Shift+S	Super+Alt+G	Super+Shift+G
Return keybind	Super+Shift+R	Steam > Exit to Desktop	Steam > Exit to Desktop

NVIDIA-Specific Notes

• Kernel parameter: nvidia-drm.modeset=1 is required. The installer can configure this for GRUB.
• Resolution cap: Gamescope on NVIDIA is limited to 2560x1440 maximum.
• Force composition: The NVIDIA wrapper automatically adds --force-composition if supported by your Gamescope version.
• Environment: GBM_BACKEND=nvidia-drm and related vars are set automatically.
• Persistence mode: Enabled during gaming to keep the GPU initialised, disabled on exit.

Troubleshooting

Verify Installation

Run the built-in verification to check all files, permissions, packages, and services:

./super_shift_g_mint.sh --verify

Common Issues

Gaming Mode doesn't start / black screen

• Check NVIDIA kernel params: cat /proc/cmdline | grep nvidia
• Verify gamescope works: gamescope -- steam
• Check session logs: journalctl --user -u gamescope-session -n 50

Apt install failures

• The installer retries with fallback mirrors automatically
• Manual recovery: sudo dpkg --configure -a && sudo apt clean && sudo apt install -y --fix-broken

Super+Shift+G doesn't work

• Log out and back in after installation
• Check Cinnamon keyboard shortcuts for "Switch to Gaming Mode"
• Verify the desktop file exists: ls /usr/share/applications/switch-to-gaming.desktop

External drives not mounting

• Ensure udisks2 is installed: dpkg -l udisks2
• Check polkit rules exist: ls /etc/polkit-1/rules.d/50-udisks-gaming.rules
• Check mount logs: journalctl -t steam-library-mount -n 20

Audio stuttering in Gaming Mode

• Check PipeWire config exists: cat /etc/pipewire/pipewire.conf.d/10-gaming-latency.conf
• Try lower quantum: edit the config and set default.clock.min-quantum = 128

"NO DICE - INTEL ONLY DETECTED"

• This system has only Intel graphics. Gaming Mode requires AMD or NVIDIA.
• If you have a discrete GPU, check that its driver is loaded: lspci -k | grep -A2 VGA

Log Locations

Component	Command
Gaming session	journalctl --user -u gamescope-session
NetworkManager	journalctl -t gamescope-nm
Drive mounting	journalctl -t steam-library-mount
Keybind monitor	journalctl -t gaming-keybind-monitor
Session wrapper	journalctl -t gamescope-wrapper
Installation	journalctl -t gaming-mode

Credits

• Linux Mint - The Ubuntu-based distribution this was adapted for
• Omarchy - Original script built for Omarchy (Arch Linux)
• ChimeraOS - gamescope-session packages
• Valve - Steam, Gamescope, and the Steam Deck inspiration

License

This project is provided as-is for the Linux Mint gaming community.