Let the headset's displays sleep when it comes off

An awake 3D mouse pointer (a connected SteamVR controller with the laser
mode forced on) kept the displays lit after the headset came off, until 30 s
without mouse input, and any bump of the mouse woke it again. Now the helper
releases the pointer as soon as SteamVR reports the headset idle and ignores
the mouse until it's worn again. The helper service also stops in 5 s
instead of waiting 90 s for its container session.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pointer/helper/frametop-pointer.service

@@ -14,6 +14,8 @@ ExecStart=%h/.local/bin/distrobox enter dev -- @REPO@/pointer/helper/build/ft-po
 ExecStopPost=-/usr/bin/pkill -x ft-pointer
 Restart=on-failure
 RestartSec=3
+# The container session (conmon) ignores SIGTERM; don't wait 90 s for it.
+TimeoutStopSec=5
 
 [Install]
 WantedBy=steamvr.service

pointer/helper/ft-pointer.cpp

@@ -31,6 +31,9 @@
 //     owns the dashboard pointer, dashboard.laserRayWidthScale is 0 so only the dot shows.
 //     It's restored when a controller takes the pointer back.
 //
+// Headset off: when SteamVR says nobody is wearing the headset, the pointer is released and
+// stays off until it's worn again, so the displays can sleep (see the main loop).
+//
 // Last used wins: when a real controller moves (picked up), the pointer is released
 // at once (driver "hide", which also drops its hand role hint), so the controller gets
 // its role and laser back. The next mouse input reconnects and claims the laser again.
@@ -366,8 +369,9 @@ int main() {
     overlay->FindOverlay("system.pointer", &systemPointer);
     Vec3 pivot, tiltOrigin, lastPoint, lastOrigin, lastAim{0, 0, -1};
     Basis tiltBasis{};
+    bool headsetOff = false;  // nobody is wearing the headset (see the main loop)
     auto wake = [&](Clock::time_point t) {
-        if (t < noWakeUntil) return;
+        if (t < noWakeUntil || headsetOff) return;
         wokeAt = t;
         active = true;
         recenter = true;
@@ -537,6 +541,24 @@ int main() {
     std::fflush(stdout);
 
     while (true) {
+        // The headset off: SteamVR drops the HMD's activity to idle as soon as it comes off.
+        // An awake pointer (a connected controller, SteamVR's laser mode forced on) kept the
+        // displays from sleeping, so it's released at once, and the mouse can't wake it until
+        // the headset is back on (then the first mouse input does).
+        const auto level = sys->GetTrackedDeviceActivityLevel(vr::k_unTrackedDeviceIndex_Hmd);
+        headsetOff = level == vr::k_EDeviceActivityLevel_Idle || level == vr::k_EDeviceActivityLevel_Standby ||
+                     level == vr::k_EDeviceActivityLevel_Idle_Timeout;
+        if (headsetOff && active) {
+            active = false;
+            claimPending = claimHeld = false;
+            overlay->HideOverlay(cursor);
+            overlay->HideOverlay(marker);
+            SendTo(out, "ft_pointer", "btn a 0");
+            SendTo(out, "ft_pointer", "hide");
+            std::printf("headset off: pointer released\n");
+            std::fflush(stdout);
+        }
+
         // Commands from the relay.
         char buf[256];
         ssize_t n;