This repository has no description
machines.coaxmetal: gamescope-session kiosk so games skip per-game gamescope
Replace the cage kiosk with a gamescope session on DRM (greetd autologin).
gamescope presents straight to the display, so there is no nested Wayland
swapchain for RADV to storm on this Vega iGPU - which crashed games like Baba
Is You when gamescope was nested under cage. Set STROM_NO_GAMESCOPE=1 so the
launcher runs <slug>.no-gamescope and each game renders directly in the session
compositor instead of nesting its own gamescope.
Runs the patched launcher from the /home/strom/strom checkout until the
STROM_NO_GAMESCOPE support lands upstream (github launcher lacks it).
author
lassulus
date
(Jul 25, 2026, 11:28 PM CEST)
commit
0e353ca7
0e353ca7963465acaa0175069164374adb005073
parent
93df609c
93df609c95c8f58d63bba747e9ad9d31623701ca
+59
-25
+59
-25
machines/coaxmetal/strom.nix
+59
-25
machines/coaxmetal/strom.nix
···
1
1
{
2
2
config,
3
-
lib,
4
3
pkgs,
5
4
...
6
5
}:
7
6
let
8
-
# Always pull the newest launcher straight from the public flake instead of
9
-
# pinning it as an input, so the game grid tracks upstream on every (re)launch.
10
-
# The launcher itself only shells out to `nix run <flake>#<slug>` per game, so
11
-
# its closure stays tiny; games bring their own nested gamescope/proton.
7
+
# Run the patched launcher from the on-disk strom checkout at
8
+
# /home/strom/strom (it carries STROM_NO_GAMESCOPE support until that lands
9
+
# upstream). With the kiosk itself being a gamescope session (below), games
10
+
# are launched as <slug>.no-gamescope so they render directly in the session
11
+
# compositor instead of nesting a per-game gamescope.
12
12
strom-session = pkgs.writeShellScript "strom-session" ''
13
13
set -u
14
14
# xpadneo owns the Xbox pad's hidraw node, so force SDL (pygame launcher and
···
23
23
# joystick (not keyboard) events while unfocused - so keyboard works but the
24
24
# pad does not. Allow joystick events regardless of focus.
25
25
export SDL_JOYSTICK_ALLOW_BACKGROUND_EVENTS=1
26
-
# Relaunch whenever the couch launcher exits (gamepad B / Esc) so the kiosk
27
-
# never drops to a blank tty. Keeping the loop as cage's child means the
28
-
# compositor stays up across relaunches.
29
-
while true; do
30
-
${config.nix.package}/bin/nix run --refresh github:kraftwerk-gaming/strom#scripts.launcher
31
-
sleep 2
26
+
# The kiosk compositor is already gamescope on DRM (see services.greetd
27
+
# below), so tell the launcher to run games directly in it rather than
28
+
# nesting a per-game gamescope (which double-nests and, on this GPU, storms
29
+
# the Vulkan swapchain and crashes games like Baba Is You).
30
+
export STROM_NO_GAMESCOPE=1
31
+
# strom-run (the per-game supervisor) needs a delegated cgroup v2 so it can
32
+
# mkdir a child cgroup and cgroup.kill the game tree atomically. The greetd
33
+
# PAM session drops us into a root-owned logind session scope
34
+
# (user-1011.slice/session-cN.scope) that is NOT delegated, so strom-run dies
35
+
# with "could not create cgroup (Permission denied)" and the game never
36
+
# launches. Re-parent into a delegated transient scope under the user manager
37
+
# (user@UID.service, which logind DOES delegate). Wait for the user bus first:
38
+
# on boot the PAM session opens slightly before the user manager's bus socket.
39
+
rd="''${XDG_RUNTIME_DIR:-/run/user/$(id -u)}"
40
+
for _ in $(seq 1 50); do
41
+
[ -S "$rd/bus" ] && break
42
+
sleep 0.2
32
43
done
44
+
# Relaunch whenever the couch launcher exits (gamepad B / Esc) so the kiosk
45
+
# never drops to a blank screen. The loop runs inside the delegated scope so
46
+
# every game inherits a writable cgroup; the gamescope compositor stays up
47
+
# (it is the session's other child) across relaunches.
48
+
#
49
+
# setpriv --ambient-caps=-all: the login session may carry an ambient
50
+
# capability (e.g. cap_wake_alarm) that every child inherits. bwrap refuses
51
+
# to start when it sees capabilities in its permitted set without being
52
+
# setuid ("Unexpected capabilities but not setuid, old file caps config?"),
53
+
# which instant-crashes every sandboxed game. Drop the ambient set for the
54
+
# whole launcher tree so bwrap (and thus each game) starts clean.
55
+
exec ${pkgs.systemd}/bin/systemd-run --user --scope -p Delegate=yes \
56
+
--quiet --collect -- \
57
+
${pkgs.util-linux}/bin/setpriv --ambient-caps=-all \
58
+
${pkgs.bash}/bin/bash -c 'while true; do
59
+
${config.nix.package}/bin/nix run /home/strom/strom#scripts.launcher
60
+
sleep 2
61
+
done'
33
62
'';
34
63
35
64
# Bluetooth pairing helper for Xbox Wireless Controllers. Run `strom-pair`
···
146
175
];
147
176
};
148
177
149
-
# Kiosk autostart. After the initrd ZFS/LUKS unlock hands off to the running
150
-
# system, graphical.target pulls up cage on tty1, which logs the strom user
151
-
# in with no prompt and runs the fullscreen launcher as its sole Wayland
152
-
# client. This is the canonical NixOS single-app kiosk path.
153
-
services.cage = {
178
+
# Kiosk autostart: a gamescope session on DRM (via greetd autologin),
179
+
# replacing cage. gamescope presents straight to the display, so there is no
180
+
# nested Wayland swapchain for RADV to storm on this Vega iGPU. greetd gives
181
+
# the strom user a real seat/VT (DRM master) and a delegated user manager,
182
+
# which the launcher's systemd-run --user --scope relies on for game cgroups.
183
+
services.greetd = {
154
184
enable = true;
155
-
user = "strom";
156
-
program = strom-session;
157
-
};
158
-
159
-
# Recover the compositor itself if it ever crashes (the session loop above
160
-
# already handles a launcher exit without tearing cage down).
161
-
systemd.services.cage-tty1.serviceConfig = {
162
-
Restart = lib.mkDefault "always";
163
-
RestartSec = 2;
185
+
settings =
186
+
let
187
+
session = {
188
+
command = "${pkgs.gamescope}/bin/gamescope -- ${strom-session}";
189
+
user = "strom";
190
+
};
191
+
in
192
+
{
193
+
# initial_session autologins on boot with no prompt; default_session
194
+
# re-runs it (also autologin) if the gamescope session ever exits.
195
+
initial_session = session;
196
+
default_session = session;
197
+
};
164
198
};
165
199
166
200
# The panel comes up at ~1% backlight, unreadable for a couch setup. Ship