feat: NVIDIA fix for gaming mode (kernel parameters and early modules)

Untested on hardware; .no-release-yet keeps it out of the release.

.no-release-yet

@@ -0,0 +1,3 @@
+This branch is not ready to be released: do not merge it into the release branch.
+When the feature is complete and tested, ask the user whether it may be released;
+on a yes, delete this file, then open the pull request into the release branch.

AGENTS.md

@@ -127,6 +127,11 @@ gamescope and the Plasma desktop. Primary target: the Valve Steam Machine
       it. Only the
       release branch's pull request into `main` is the user's: never commit
       or merge to `main`, the user merges that one.
+      A `.no-release-yet` file at the root of a feature/bugfix branch means
+      it must not be merged into the release branch yet (work in progress,
+      untested on hardware). When the feature is complete, ask the user
+      whether it may be released; on a yes, delete the file, then open the
+      pull request and merge it.
       Keep a feature/bugfix branch up to date by merging (or rebasing on)
       its release branch, the release branch by merging `main` when that
       moved.

CHANGELOG.md

@@ -7,6 +7,8 @@ one per merged pull request.
 
 ## 2.9.7 - 2026-10-01
 
+- **feat: the SteamOS conversion fixes a corrupted gaming mode screen with an NVIDIA GPU: nvidia-drm.modeset=1 and fbdev=1 on the kernel command line, NVIDIA modules in the initramfs (lib/nvidia.sh)**
+
 ## 2.9.6 - 2026-09-30
 
 - **fix(ci): a dev ISO from a release branch is built with that branch's own Steamify (input steamify_ref of the ISO workflow), not the newest published release: release/2.9.6 kept producing 2.9.5 ISOs**

TECHNICAL.md

@@ -206,6 +206,19 @@ or upgraded. A newly added kernel doesn't come with its headers, so
 `ensure-kernel-headers.service` checks at every boot and installs any
 missing `-headers` package, which makes DKMS build the driver for it.
 
+## NVIDIA fix for gaming mode
+
+gamescope drives the display itself through DRM/KMS, which with NVIDIA needs
+kernel modesetting and the framebuffer driver, and the driver loaded early;
+without them gaming mode can show a corrupted image. With an NVIDIA GPU and
+its driver installed (`lib/nvidia.sh`), the SteamOS conversion adds
+`nvidia-drm.modeset=1 nvidia-drm.fbdev=1` to the kernel command line (Limine,
+systemd-boot or GRUB; the file is backed up first) and
+`/etc/mkinitcpio.conf.d/90-steamify-nvidia.conf` (`MODULES+=(nvidia
+nvidia_modeset nvidia_uvm nvidia_drm)`), then rebuilds the initramfs and boot
+entries. Only what's missing is changed; it applies after a reboot. Turning
+the conversion off removes both. Untested on hardware so far.
+
 ## HDMI-CEC
 
 The **HDMI-CEC** item (on every PC; ticked by default only on a Steam
@@ -510,6 +523,7 @@ immediately, which can turn into a loop - see
 | `lib/steam-game.sh` | Add as non-Steam game: Steamify in the Steam library (`patches/steam-shortcuts.py`) |
 | `lib/update-notifier.sh` | Update notifications: the notifier from `patches/` and its user timer |
 | `lib/first-login.sh` | `--defaults` without a session (the Steam Machine ISO's installer): the one-time first-login step that sets up single user's launcher on Plasma's new layout and opens the app |
+| `lib/nvidia.sh` | NVIDIA fix for gaming mode: kernel parameters and early modules (part of the SteamOS conversion) |
 | `lib/vram-booster.sh` | VRAM booster (`dmemcg-booster`, `plasma-foreground-booster`) |
 | `services/` | The systemd units the scripts install (`service_file`, `@KEY@` placeholders); see its README |
 | `patches/` | Module sources and patches the scripts build or apply (`patch_file`); see its README |

lib/login-manager.sh

@@ -109,6 +109,7 @@ gaming_enable() {
     esac
     create_desktop_shortcut
     steam_enable
+    nvidia_enable || return 1
     os_name_enable || return 1
 }
 
@@ -124,6 +125,7 @@ gaming_disable() {
     steam_disable
     krevert gaming
     os_name_disable
+    nvidia_disable
     ok "The PC boots to the normal login screen again (from the next boot)."
 }
 

lib/menu.sh

@@ -25,7 +25,7 @@ NO_PRESELECT=(boot cec kpin hdmi)
 # FEATURE_BASELINE.
 FEATURE_BASELINE=2.1.0
 declare -A FEATURE_VERSION=(
-    [gaming]=2.9.0 [boot]=2.1.0 [theme]=2.1.0 [glyphs]=2.1.0 [single]=2.1.0
+    [gaming]=2.9.7 [boot]=2.1.0 [theme]=2.1.0 [glyphs]=2.1.0 [single]=2.1.0
     [launcher]=2.1.0 [cec]=2.7.0 [machine]=2.9.0 [poweroff]=2.2.0 [vram]=2.3.0 [notify]=2.5.0 [steamgame]=2.5.1
     [kpin]=2.1.0 [hdmi]=2.1.0
 )

lib/nvidia.sh

@@ -0,0 +1,102 @@
+#!/bin/bash
+# NVIDIA fix for gaming mode, part of the SteamOS conversion
+# (gaming_enable/gaming_disable). gamescope drives the display itself
+# through DRM/KMS; with NVIDIA that needs kernel modesetting and the
+# framebuffer driver (nvidia-drm.modeset=1 nvidia-drm.fbdev=1) and the
+# driver in the initramfs, or the screen shows a corrupted image.
+# Does nothing without an NVIDIA GPU that has its driver installed.
+# Sourced by steamify.sh; not meant to be run on its own.
+
+NVIDIA_PARAMS="nvidia-drm.modeset=1 nvidia-drm.fbdev=1"
+NVIDIA_INITRAMFS_CONF=/etc/mkinitcpio.conf.d/90-steamify-nvidia.conf
+NVIDIA_MARK="# steamify-nvidia"
+
+nvidia_present() {
+    # An NVIDIA GPU (PCI vendor 0x10de, display class) and its kernel driver.
+    local d
+    for d in /sys/class/drm/card[0-9]*/device; do
+        [[ "$(cat "$d/vendor" 2>/dev/null)" == 0x10de ]] || continue
+        [[ "$(cat "$d/class" 2>/dev/null)" == 0x03* ]] && modinfo nvidia_drm >/dev/null 2>&1 && return 0
+    done
+    return 1
+}
+
+nvidia_boot_file() {
+    # Same boot loaders as the kernel command line elsewhere (lib/hdmi-refresh.sh).
+    hdmi_boot_file
+}
+
+nvidia_param_set() {
+    # 0 when $1 (e.g. nvidia-drm.modeset=1) is on the kernel command line or
+    # already in the boot loader's file (not booted yet).
+    local f; f="$(nvidia_boot_file)"
+    grep -qw -- "$1" /proc/cmdline 2>/dev/null ||
+        { [[ -n "$f" ]] && grep -qw -- "$1" "$f" 2>/dev/null; }
+}
+
+nvidia_params_missing() {
+    local p
+    for p in $NVIDIA_PARAMS; do nvidia_param_set "$p" || return 0; done
+    return 1
+}
+
+nvidia_initramfs_ok() {
+    [[ -f "$NVIDIA_INITRAMFS_CONF" ]] || grep -qE '^MODULES=.*nvidia_drm' /etc/mkinitcpio.conf 2>/dev/null
+}
+
+nvidia_rebuild_boot() {
+    local f; f="$(nvidia_boot_file)"
+    info "Rebuilding the initramfs and boot entries..."
+    case "$f" in
+        /etc/default/limine) sudo limine-mkinitcpio ;;
+        /etc/sdboot-manage.conf) sudo /usr/bin/mkinitcpio -P && sudo sdboot-manage gen ;;
+        /etc/default/grub) sudo /usr/bin/mkinitcpio -P && sudo grub-mkconfig -o /boot/grub/grub.cfg ;;
+        *) sudo /usr/bin/mkinitcpio -P ;;
+    esac
+}
+
+nvidia_enable() {
+    nvidia_present || return 0
+    local f changed=0 p; f="$(nvidia_boot_file)"
+    if nvidia_params_missing; then
+        if [[ -z "$f" ]]; then
+            warn "NVIDIA GPU found, but no supported boot loader: add '$NVIDIA_PARAMS' to the kernel command line yourself."
+        else
+            info "NVIDIA GPU found: adding $NVIDIA_PARAMS to the kernel command line (fixes a corrupted screen in gaming mode)..."
+            backup_file "$f"
+            case "$f" in
+                /etc/default/limine)
+                    printf 'KERNEL_CMDLINE[default]+=" %s" %s\n' "$NVIDIA_PARAMS" "$NVIDIA_MARK" | sudo tee -a "$f" >/dev/null ;;
+                /etc/sdboot-manage.conf)
+                    sudo sed -i -E "s/^(LINUX_OPTIONS=\"[^\"]*)\"/\1 $NVIDIA_PARAMS\"/" "$f" ;;
+                /etc/default/grub)
+                    sudo sed -i -E "s/^(GRUB_CMDLINE_LINUX_DEFAULT=\"[^\"]*)\"/\1 $NVIDIA_PARAMS\"/" "$f" ;;
+            esac
+            changed=1
+        fi
+    fi
+    if ! nvidia_initramfs_ok; then
+        info "Loading the NVIDIA modules early (initramfs)..."
+        printf 'MODULES+=(nvidia nvidia_modeset nvidia_uvm nvidia_drm)\n' |
+            sudo install -Dm644 /dev/stdin "$NVIDIA_INITRAMFS_CONF" && changed=1
+    fi
+    if [[ $changed == 1 ]]; then
+        nvidia_rebuild_boot || { err "Rebuilding the boot entries failed."; return 1; }
+        ok "NVIDIA gaming mode fix applied; it takes effect after a reboot."
+    fi
+    return 0
+}
+
+nvidia_disable() {
+    local f changed=0; f="$(nvidia_boot_file)"
+    if [[ -n "$f" ]] && grep -q "$NVIDIA_PARAMS" "$f" 2>/dev/null; then
+        case "$f" in
+            /etc/default/limine) sudo sed -i "/$NVIDIA_MARK\$/d" "$f" ;;
+            *) sudo sed -i "s/ \?$NVIDIA_PARAMS//" "$f" ;;
+        esac
+        changed=1
+    fi
+    [[ -f "$NVIDIA_INITRAMFS_CONF" ]] && { sudo rm -f "$NVIDIA_INITRAMFS_CONF"; changed=1; }
+    [[ $changed == 1 ]] && nvidia_rebuild_boot
+    return 0
+}

steamify.sh

@@ -19,7 +19,7 @@ VERSION=2.9.7
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-for lib in common state packages login-manager single-user steam-desktop steam-machine fremont-poweroff vram-booster hdmi-refresh cec boot-session vapor-theme steamos-extras bios desktop-shortcut wizard-shortcut steam-game update-notifier first-login menu backend; do
+for lib in common state packages login-manager single-user steam-desktop steam-machine fremont-poweroff vram-booster hdmi-refresh nvidia cec boot-session vapor-theme steamos-extras bios desktop-shortcut wizard-shortcut steam-game update-notifier first-login menu backend; do
     # shellcheck source=/dev/null
     source "$SCRIPT_DIR/lib/$lib.sh"
 done