feat: VRAM booster for the Steam Machine

AGENTS.md

@@ -231,6 +231,12 @@ gamescope and the Plasma desktop. Primary target: the Valve Steam Machine
   `linux-cachyos` is clang-built, `-bore` GCC-built: let DKMS pick the
   compiler, never pass `LLVM=1`. Test shutdown on the real machine for every
   new major kernel.
+- VRAM booster (`vram`, `lib/vram-booster.sh`, a default sub-option of
+  `machine`, 2.3.0): CachyOS's `dmemcg-booster` (system + user service) and
+  `plasma-foreground-booster`, like SteamOS 3.9's VRAM management. The
+  latter only starts with `kcgroupsrc [Foreground Booster] autostart=true`
+  (set with `kset`). Disable removes only the packages it installed
+  (`state_get vram installed_pkgs`).
 - `Relogin=true` means a gamescope that fails to start is relaunched in a
   tight loop; keep that in mind when changing session handling.
 

CHANGELOG.md

@@ -5,9 +5,13 @@ All notable changes, per version and per commit. Versions follow
 `steamify.sh`. Versions before 0.7.0 were numbered afterwards,
 one per merged pull request.
 
+## 2.3.0 - 2026-09-27
+
+- **feat: VRAM booster for the Steam Machine**
+
 ## 2.2.0 - 2026-09-27
 
-- **docs: Changelog entries per commit for 2.2.0**
+- `ef585c0` **docs: Changelog entries per commit for 2.2.0**
 - `32795bd` **feat(ui): Update badge on the progress screen**
 - `3c8ca65` **fix(ui): Never write the sudo password to a file; Update label on the progress screen**
   - The app gave `sudo` the password through a short-lived file; the helper

README.md

@@ -48,6 +48,9 @@ What Steamify can do on a Valve Steam Machine:
   - **Power-off fix** - on by default: shutting down really turns the Steam
     Machine off, also with the newest CachyOS kernel
     ([details](TECHNICAL.md#power-off-fix-steam-machine)).
+  - **VRAM booster** - on by default: the game you're playing keeps its
+    video memory and background apps make room, like SteamOS 3.9
+    ([details](TECHNICAL.md#vram-booster-steam-machine)).
   - **Update BIOS** - installs Valve's newest Steam Machine BIOS. Never ticked
     by default, at your own risk, and only after two warnings
     ([details](TECHNICAL.md#bios-updates-steam-machine)).

TECHNICAL.md

@@ -236,6 +236,29 @@ Where Steam Machine support was set up before 2.2.0, the menu ticks the
 power-off fix as a new default sub-option (see feature versions below), so a
 normal run adds it.
 
+## VRAM booster (Steam Machine)
+
+SteamOS 3.9 manages the dGPU's VRAM per cgroup: the game in front is
+protected, background apps are evicted first. Without it a game that needs
+most of the Steam Machine's 8 GB can be pushed into system RAM by the
+desktop and other apps, and stutter. The kernel side is the `dmem` cgroup
+controller (7.2); CachyOS packages the userspace side, which the **VRAM
+booster** sub-option of Steam Machine support installs (ticked along with
+it, can be unticked; new in 2.3.0, so existing setups get it ticked):
+
+- `dmemcg-booster`: `dmemcg-booster-system.service` enables the `dmem`
+  controller and sets `dmem.low` for the cgroup in front;
+  `dmemcg-booster-user.service` runs in the user session.
+- `plasma-foreground-booster`: tells it which window is in front on the
+  desktop. It only starts with `autostart=true` under `[Foreground Booster]`
+  in `kcgroupsrc`, which the wizard sets (and reverts).
+
+Check it with `cat /sys/fs/cgroup/cgroup.subtree_control` (lists `dmem`) and
+the `dmem.low` of the slices under `user@<uid>.service`. Turning it off
+disables the services and removes the packages the wizard installed.
+Not added: a fixed `dmem.max` cap for `app.slice` (as some guides do); only
+worth it if the booster itself turns out to cause stutter.
+
 ## Feature versions (updates)
 
 Each component has a feature version (`FEATURE_VERSION` in `lib/menu.sh`):
@@ -327,6 +350,7 @@ immediately, which can turn into a loop - see
 | `lib/cec.sh` | HDMI-CEC: Valve's `cecd` and friends from its `holo` repository |
 | `lib/steam-machine.sh` | Steam Machine support: LED driver, LED access, steamos-manager |
 | `lib/fremont-poweroff.sh` | Steam Machine support: the power-off fix (DKMS module from `patches/`) |
+| `lib/vram-booster.sh` | Steam Machine support: the VRAM booster (`dmemcg-booster`, `plasma-foreground-booster`) |
 | `patches/` | Module sources and patches the scripts build or apply (`patch_file`); see its README |
 | `.github/tools/bundle.sh` | Builds the single-file version (`dist/steamify.sh`), with `patches/` embedded |
 | `.github/workflows/bundle.yml` | Builds and checks it on every push; publishes it on `main` |

lib/backend.sh

@@ -162,7 +162,8 @@ backend_apply() {
     [[ "${WANTED[single]:-0}" == 1 ]] && WANTED[gaming]=1
     [[ "${WANTED[gaming]:-0}" == 0 ]] && { WANTED[single]=0; WANTED[boot]=0; }
     [[ "${WANTED[poweroff]:-0}" == 1 ]] && WANTED[machine]=1
-    [[ "${WANTED[machine]:-0}" == 0 ]] && WANTED[poweroff]=0
+    [[ "${WANTED[vram]:-0}" == 1 ]] && WANTED[machine]=1
+    [[ "${WANTED[machine]:-0}" == 0 ]] && { WANTED[poweroff]=0; WANTED[vram]=0; }
     [[ "${WANTED[kpin]:-0}" == 1 ]] && WANTED[machine]=1
     [[ "${WANTED[machine]:-0}" == 0 ]] && WANTED[kpin]=0
     [[ "${WANTED[hdmi]:-0}" == 1 ]] && { WANTED[machine]=1; WANTED[kpin]=1; }

lib/menu.sh

@@ -5,12 +5,12 @@
 
 # Menu order. Components are turned on in this order and off in reverse;
 # gaming must come first (single user builds on it).
-COMPONENTS=(gaming boot theme glyphs single launcher cec machine poweroff kpin hdmi bios)
+COMPONENTS=(gaming boot theme glyphs single launcher cec machine poweroff vram kpin hdmi bios)
 # One-off actions rather than on/off components: never preselected, never
 # re-applied, not listed as on or off.
 ACTIONS=(bios)
 # Sub-options, shown indented under their parent and only while it's ticked.
-declare -A PARENT=([boot]=gaming [poweroff]=machine [kpin]=machine [hdmi]=machine [bios]=machine)
+declare -A PARENT=([boot]=gaming [poweroff]=machine [vram]=machine [kpin]=machine [hdmi]=machine [bios]=machine)
 # Never preselected on a first run: booting into the desktop is a choice,
 # gamescope is the default; HDMI-CEC is opt-in (it can wake the machine or
 # upset other devices on the TV, even on SteamOS), except on a Steam Machine,
@@ -26,7 +26,7 @@ NO_PRESELECT=(boot cec kpin hdmi)
 FEATURE_BASELINE=2.1.0
 declare -A FEATURE_VERSION=(
     [gaming]=2.1.0 [boot]=2.1.0 [theme]=2.1.0 [glyphs]=2.1.0 [single]=2.1.0
-    [launcher]=2.1.0 [cec]=2.1.0 [machine]=2.2.0 [poweroff]=2.2.0
+    [launcher]=2.1.0 [cec]=2.1.0 [machine]=2.2.0 [poweroff]=2.2.0 [vram]=2.3.0
     [kpin]=2.1.0 [hdmi]=2.1.0
 )
 
@@ -40,6 +40,7 @@ declare -A LABEL=(
     [cec]="HDMI-CEC: use Steam with the TV remote, TV on/off with the PC (experimental)"
     [machine]="Steam Machine support: LED bar driver, hardware settings in Steam"
     [poweroff]="Power-off fix: the Steam Machine stays off after shutting down"
+    [vram]="VRAM booster: the game in front keeps its VRAM, background apps make room"
     [kpin]="Pin the kernel to $PINNED_KERNEL_VER (untick for CachyOS's current kernel)"
     [hdmi]="HDMI refresh boost: highest refresh your HDMI display runs"
     [bios]="Update BIOS"
@@ -48,7 +49,7 @@ declare -A CURRENT WANTED
 
 component_available() {
     case "$1" in
-        machine|poweroff) machine_available ;;
+        machine|poweroff|vram) machine_available ;;
         kpin) kpin_available ;;
         hdmi) hdmi_available ;;
         bios) bios_available ;;
@@ -157,9 +158,11 @@ toggle_component() {
     if [[ "$c" == gaming && "${WANTED[gaming]}" == 0 ]]; then WANTED[single]=0; WANTED[boot]=0; fi
     # Where to boot to is part of the conversion, too.
     if [[ "$c" == boot && "${WANTED[boot]}" == 1 ]]; then WANTED[gaming]=1; fi
-    # The power-off fix is opt-out: ticked along with Steam Machine support.
+    # The power-off fix and VRAM booster are opt-out: ticked along with
-    if [[ "$c" == machine ]]; then WANTED[poweroff]=${WANTED[machine]}; fi
+    # Steam Machine support.
+    if [[ "$c" == machine ]]; then WANTED[poweroff]=${WANTED[machine]}; WANTED[vram]=${WANTED[machine]}; fi
     if [[ "$c" == poweroff && "${WANTED[poweroff]}" == 1 ]]; then WANTED[machine]=1; fi
+    if [[ "$c" == vram && "${WANTED[vram]}" == 1 ]]; then WANTED[machine]=1; fi
     if [[ "$c" == machine && "${WANTED[machine]}" == 0 ]]; then WANTED[kpin]=0; fi
     if [[ "$c" == kpin && "${WANTED[kpin]}" == 1 ]]; then WANTED[machine]=1; fi
     # HDMI refresh boost and the BIOS update sit under Steam Machine support;

lib/vram-booster.sh

@@ -0,0 +1,51 @@
+#!/bin/bash
+# "VRAM booster" menu item (vram), a sub-option of Steam Machine support
+# ticked along with it (opt-out), like SteamOS 3.9's dGPU VRAM management:
+# the game in front keeps its VRAM, background apps are evicted first, so a
+# game on the 8 GB GPU doesn't spill into system RAM and stutter. The kernel
+# side is the dmem cgroup controller (7.2); CachyOS packages the userspace
+# side: dmemcg-booster (a system service that enables the controller and
+# sets the limits, plus a user service) and plasma-foreground-booster, which
+# tells it which window is in front on the desktop. The latter only starts
+# with "autostart" set in kcgroupsrc.
+# Sourced by steamify.sh; not meant to be run on its own.
+
+VRAM_PKGS=(dmemcg-booster plasma-foreground-booster)
+
+vram_status() {
+    pacman -Q "${VRAM_PKGS[@]}" >/dev/null 2>&1 &&
+        systemctl is-enabled -q dmemcg-booster-system.service 2>/dev/null &&
+        systemctl --user is-enabled -q dmemcg-booster-user.service 2>/dev/null
+}
+
+vram_enable() {
+    local p missing=()
+    info "Installing the VRAM booster (the game in front keeps its VRAM)..."
+    for p in "${VRAM_PKGS[@]}"; do pacman -Q "$p" >/dev/null 2>&1 || missing+=("$p"); done
+    if ((${#missing[@]})); then
+        sudo pacman -S --needed --noconfirm "${missing[@]}" ||
+            { err "Installing ${missing[*]} failed."; return 1; }
+        state_set vram installed_pkgs "${missing[*]}"
+    fi
+    sudo systemctl enable --now dmemcg-booster-system.service >/dev/null 2>&1 ||
+        { err "Starting dmemcg-booster failed."; return 1; }
+    systemctl --user enable --now dmemcg-booster-user.service >/dev/null 2>&1 ||
+        { err "Starting dmemcg-booster for $USER failed."; return 1; }
+    kset vram kcgroupsrc "Foreground Booster" autostart true
+    # Started by the Plasma session from now on; start it in this one too.
+    [[ "${XDG_CURRENT_DESKTOP:-}" == KDE ]] &&
+        systemctl --user start plasma-foreground-booster.service >/dev/null 2>&1
+    ok "VRAM booster on: the game in front keeps its VRAM."
+}
+
+vram_disable() {
+    local pkgs
+    systemctl --user disable --now plasma-foreground-booster.service dmemcg-booster-user.service >/dev/null 2>&1
+    sudo systemctl disable --now dmemcg-booster-system.service >/dev/null 2>&1
+    krevert vram
+    pkgs="$(state_get vram installed_pkgs)"
+    # shellcheck disable=SC2086 # a list of package names
+    [[ -n "$pkgs" ]] && sudo pacman -Rns --noconfirm $pkgs >/dev/null 2>&1
+    state_clear vram
+    ok "VRAM booster off."
+}

steamify.sh

@@ -15,11 +15,11 @@
 set -uo pipefail
 
 # Release version, see CHANGELOG.md.
-VERSION=2.2.0
+VERSION=2.3.0
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-for lib in common state packages login-manager single-user steam-desktop steam-machine fremont-poweroff hdmi-refresh cec boot-session vapor-theme steamos-extras bios desktop-shortcut wizard-shortcut menu backend; do
+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 menu backend; do
     # shellcheck source=/dev/null
     source "$SCRIPT_DIR/lib/$lib.sh"
 done

ui/qml/Main.qml

@@ -72,6 +72,9 @@ ApplicationWindow {
         poweroff: { label: "Power-off fix", hint: "Stays off after shutting down",
                     body: "With recent kernels the Steam Machine starts again right after shutting down: the firmware leaves a wake bit set, and newer kernels (7.2, and updates of 6.x, 7.0 and 7.1) no longer clear it. Valve's own kernel clears it; this small module does the same right before power-off.",
                     changes: ["steamify-fremont-poweroff module for each installed kernel (DKMS)", "Only on a Steam Machine, only touches that one wake bit", "Off: recent kernels may start it again after shutting down"] },
+        vram: { label: "VRAM booster", hint: "The game in front keeps its VRAM",
+                body: "Like SteamOS 3.9: the game you're playing keeps its video memory, and background apps are moved out first. Without it a game that needs most of the 8 GB can spill into system RAM and stutter.",
+                changes: ["dmemcg-booster (system and user service)", "plasma-foreground-booster, which tells it which window is in front", "Off: removed again, unless you had installed them yourself"] },
         kpin: { label: "Pin the kernel", hint: "Untick for CachyOS's current kernel",
                 body: "Keeps the Steam Machine on CachyOS kernel 7.1.6. Untick it to go back to CachyOS's current kernel; HDMI refresh boost goes with it.",
                 changes: ["linux-cachyos from Steamify's release (signature checked)", "Kept in /var/cache/steamify/kernel", "Added to IgnorePkg"] },
@@ -250,8 +253,9 @@ ApplicationWindow {
         if (id === "hdmi" && !hdmiChoice && hdmiSaved.length) { openHdmiList(); return; }
         if (id === "hdmi" && w.hdmi && !nowOn("hdmi") && !hdmiChoice) { startHdmi(); return; }
         if (id === "hdmi" && !w.hdmi) hdmiChoice = "";
-        if (id === "machine") w.poweroff = w.machine;
+        if (id === "machine") { w.poweroff = w.machine; w.vram = w.machine; }
         if (id === "poweroff" && w.poweroff) w.machine = true;
+        if (id === "vram" && w.vram) w.machine = true;
         if (id === "machine" && !w.machine) w.kpin = false;
         if (id === "kpin" && w.kpin) w.machine = true;
         if (id === "hdmi" && w.hdmi) { w.machine = true; w.kpin = true; }