Merge main into desktop capture evidence PR

Co-authored-by: SAPHID <saphid@users.noreply.github.com>

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 ## Unreleased
 
+- Record packaged v0.4.17 Desktop Capture succeeding on a mapped nested KDE
+  compositor on a real Frame with SteamOS 0.5.6. Headset overlay visibility was
+  not established; this is evidence, not a new fix or resolution of issue #73.
+
+- Correct the Return to Game Mode help text: Frame Control selects the switch
+  supported by the headset's SteamOS build, including `steamosctl` on current
+  Frames. The button's behavior is unchanged.
+
 - Distinguish an unreadable gamescope panel list from a confirmed empty list in
   Desktop Capture and Control (issue #73). Failed discovery now asks users to
   check SteamVR and report the exact message and SteamOS version, rather than

docs/backup-and-recovery.md

@@ -25,8 +25,28 @@ tested in another full Plasma session under a three-minute rollback timer.
 `ui/frame_backup.py session` reported Desktop Mode despite gamescope, and
 `ui/frame_backup.py game-mode` invoked the same guarded Return function used by
 the button. Game Mode became active and a second call made no switch. Battery
-remained at 99%; the timer and lock were removed. The literal desktop button
-was not clicked in this test, and older SteamOS builds remain fixture-tested.
+remained at 99%; the timer and lock were removed. That test used the production
+CLI rather than clicking the desktop button.
+
+Later on 2026-10-24, the published **v0.4.17 Linux x86_64 AppImage** passed the
+literal packaged-button check on the same Frame/build. With the shared lock and
+a verified three-minute rollback timer, the headset entered full Plasma Desktop
+Mode. In the packaged Electron window, **Tools → Backup & recovery → Check**
+reported Desktop Mode despite gamescope. A trusted automated pointer click on
+the visible **Return to Game Mode** button, accepting its confirmation, returned
+`switched: true` and `steamosctl switch-to-game-mode`. The systemd targets then
+confirmed Game Mode. A second confirmed button click returned `switched: false`;
+the Game Mode service invocation and SteamVR PID stayed unchanged. **Check**
+then reported Game Mode and disabled Return. The test app/server and virtual
+display were stopped; the timer and shared lock were removed. Steam and SteamVR remained running
+at 99% battery. [Commands, responses, cleanup and limits](evidence/return-game-mode-packaged-2026-10-24.json),
+[before](evidence/return-game-mode-packaged-2026-10-24-before.png) and
+[after](evidence/return-game-mode-packaged-2026-10-24-after.png).
+
+This used the unchanged extracted AppImage payload with its bundled Python on
+Xvfb (`--no-sandbox --disable-gpu`), following the packaged Export test in #156.
+FUSE mounting, desktop integration, hardware rendering and the view inside a
+worn headset were not checked. Older SteamOS builds remain fixture-tested.
 
 ## Back up
 

docs/evidence/desktop-capture-packaged-2026-10-24.json

@@ -0,0 +1,206 @@
+{
+  "date_utc": "2026-10-24",
+  "base_commit": "de931bc",
+  "issue": 73,
+  "result": "Packaged Desktop Capture passed for a mapped nested KDE compositor on the real Frame; wearer-visible overlay condition was not established. Do not close #73 from this test.",
+  "package": {
+    "tag": "v0.4.17",
+    "asset": "Frame-Control-linux-x86_64.AppImage",
+    "sha256": "b1b8eb82bf73a227b2cd36e8f0ef3a2ebdf7967c5853efb08a9634f38227015d",
+    "release_digest_matched": true,
+    "panel_helper_matches_base": true,
+    "unmodified_payload": true,
+    "host": "lxso2",
+    "display": "Xvfb :139",
+    "flags": [
+      "--no-sandbox",
+      "--disable-gpu"
+    ],
+    "private_profile_and_data": true,
+    "telemetry_and_update_checks_disabled": true
+  },
+  "preflight": {
+    "steamos_version": "0.5.6",
+    "build_id": "20261015.6141207",
+    "battery_percent": 99,
+    "battery_status": "Not charging",
+    "game_mode": true,
+    "full_plasma_session": false,
+    "nested_desktop_running": false,
+    "nested_runtime_present": false,
+    "lock_present": false,
+    "steam_pid": 297826,
+    "vrserver_pid": 297506,
+    "vrcompositor_pid": 297620,
+    "gamescope_service_invocation": "e8c1085b3bbd4e79a323b3e4a9bc6355",
+    "focusable_windows": [],
+    "focused_windows": []
+  },
+  "session": {
+    "started_utc": "2026-10-24T09:43:48Z",
+    "lock_acquired": true,
+    "launch": [
+      "systemd-run",
+      "--user",
+      "--unit=fc-issue73-desktop-20261024",
+      "--collect",
+      "--property=RuntimeMaxSec=180s",
+      "--property=TimeoutStopSec=15s",
+      "--property=KillMode=control-group",
+      "--setenv=DISPLAY=:0",
+      "--setenv=XDG_RUNTIME_DIR=/run/user/1000",
+      "--setenv=DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus",
+      "--setenv=XDG_SESSION_TYPE=x11",
+      "--setenv=XDG_CURRENT_DESKTOP=gamescope",
+      "/usr/bin/steamos-nested-desktop"
+    ],
+    "response": "Running as unit: fc-issue73-desktop-20261024.service; invocation ID: 92cff1e57c794212997d46c0a68877ec\n"
+  },
+  "discovery": {
+    "focus": 62914560,
+    "focus_display": ":0",
+    "panels": [
+      {
+        "window": 62914560,
+        "display": ":0",
+        "name": "KDE Wayland Compositor - Press right control key to grab input",
+        "x": 0,
+        "y": 0,
+        "width": 1920,
+        "height": 1080,
+        "app": 0,
+        "focused": true
+      }
+    ]
+  },
+  "window_evidence": {
+    "xwininfo_map_state": "IsViewable",
+    "width": 1920,
+    "height": 1080,
+    "focused_after_show_request": true,
+    "steamvr_overlay_key": "valve.steam.desktopgame.0",
+    "steamvr_overlay_visibility_after_show_request": "not_visible"
+  },
+  "capture": {
+    "repeat_utc": "2026-10-24T09:44:47.323Z",
+    "route": "/api/screenshot?view=panel&window=62914560&display=%3A0",
+    "http": 200,
+    "content_type": "image/png",
+    "content_length": 1209980,
+    "source_header": "panel",
+    "decoded": {
+      "width": 1920,
+      "height": 1080,
+      "source": "panel",
+      "selected": {
+        "window": 62914560,
+        "display": ":0",
+        "name": "KDE Wayland Compositor - Press right control key to grab input",
+        "x": 0,
+        "y": 0,
+        "width": 1920,
+        "height": 1080,
+        "app": 0,
+        "focused": true
+      },
+      "stamp": "9:44:48 AM",
+      "badge": "Desktop \u00b7 KDE Wayland Compositor - Press right control key to grab input"
+    },
+    "canvas_png_bytes": 2011278,
+    "first_capture_pixel_statistics": {
+      "width": 1920,
+      "height": 1080,
+      "min": 2.3333333333333335,
+      "max": 255,
+      "hidden": false
+    },
+    "first_capture_click_event": {
+      "isTrusted": true,
+      "utc": "2026-10-24T09:44:12.738Z"
+    },
+    "actions": "Two Playwright locator.click() actions on the visible #shotBtn in the actual packaged Electron window; first click recorded isTrusted=true. No direct screenshot API invocation by harness."
+  },
+  "device_cleanup": {
+    "utc": "2026-10-24T09:45:33Z",
+    "before_stop": {
+      "exit": 0,
+      "out": "MainPID=300739\nControlGroup=/user.slice/user-1000.slice/user@1000.service/app.slice/fc-issue73-desktop-20261024.service\nActiveState=active\n",
+      "err": ""
+    },
+    "hide_dashboard": {
+      "exit": 0,
+      "out": "HideDashboard",
+      "err": ""
+    },
+    "stop_owned_unit": {
+      "exit": 0,
+      "out": "",
+      "err": ""
+    },
+    "after_stop": {
+      "exit": 0,
+      "out": "MainPID=0\nLoadState=not-found\nActiveState=inactive\n",
+      "err": ""
+    },
+    "desktop_processes": {
+      "exit": 1,
+      "out": "",
+      "err": ""
+    },
+    "nested_runtime_exists": false,
+    "session": {
+      "exit": 0,
+      "out": "Id=gamescope-session.target\nActiveState=active\nInvocationID=a2fee8ebf55c42c7b546390d14cd985c\n\nId=plasma-workspace-wayland.target\nActiveState=inactive\nInvocationID=\n\nId=gamescope-session.service\nActiveState=active\nInvocationID=e8c1085b3bbd4e79a323b3e4a9bc6355\n",
+      "err": ""
+    },
+    "steam": {
+      "exit": 0,
+      "out": "297826 /home/steamos/.local/share/Steam/steamrtarm64/steam -cef-enable-debugging -deckard -gamepadui -steamdeck -steamos3 -vrgamepadui\n",
+      "err": ""
+    },
+    "steamvr": {
+      "exit": 0,
+      "out": "297506 /opt/steamvr/bin/linuxarm64/vrserver -waitformonitor -ipccontrolfilepath /tmp/SteamVR-IPCControlFile-297420\n297620 /opt/steamvr/bin/linuxarm64/vrcompositor\n",
+      "err": ""
+    },
+    "xprops": {
+      "exit": 0,
+      "out": "GAMESCOPE_FOCUSABLE_WINDOWS(CARDINAL) = \nGAMESCOPE_FOCUSED_WINDOW(CARDINAL) = \n",
+      "err": ""
+    },
+    "battery": {
+      "capacity": "99",
+      "status": "Not charging"
+    },
+    "owned_lock_released": true
+  },
+  "host_cleanup": {
+    "electron": {
+      "pid": 1578431,
+      "exists_after": false
+    },
+    "xvfb": {
+      "pid": 1578428,
+      "exists_after": false
+    },
+    "x_socket_absent": true
+  },
+  "delayed_final_readback": "2026-10-24T09:46:39Z\nshared-lock-absent\nLoadState=not-found\nActiveState=inactive\nId=gamescope-session.target\nActiveState=active\n\nId=plasma-workspace-wayland.target\nActiveState=inactive\nInvocationID=e8c1085b3bbd4e79a323b3e4a9bc6355\n297826 /home/steamos/.local/share/Steam/steamrtarm64/steam -cef-enable-debugging -deckard -gamepadui -steamdeck -steamos3 -vrgamepadui\n297506 /opt/steamvr/bin/linuxarm64/vrserver -waitformonitor -ipccontrolfilepath /tmp/SteamVR-IPCControlFile-297420\n297620 /opt/steamvr/bin/linuxarm64/vrcompositor\nnested-runtime-absent\n100\nFull\nGAMESCOPE_FOCUSABLE_WINDOWS(CARDINAL) = \nGAMESCOPE_FOCUSED_WINDOW(CARDINAL) = \n",
+  "validation": {
+    "focused_panel_suite": "42 tests passed in 14.805s (test_touch.py), including production-page Node behavior tests",
+    "website": "2 tests passed (node --test site/test/*.test.mjs)",
+    "node_panels": "Passed independently (node tests/page/desk_panels.mjs)",
+    "metadata_and_links": "JSON parsed; result/cleanup assertions and relative evidence/streaming/testing links passed",
+    "diff": "git diff --check passed"
+  },
+  "limits": [
+    "SteamVR continued reporting not_visible after ShowDashboard, despite mapped X window and confirmed focus. No worn-headset visual assessment; does not establish the reporter's visible-overlay condition.",
+    "SteamOS 0.5.6 only; reporter used 0.4.5 with unknown Frame Control version and no reproduction steps.",
+    "Nested desktop launched with SteamOS steamos-nested-desktop from a bounded transient user unit using Steam display/session variables; not launched through a wearer's Steam UI.",
+    "Extracted unchanged AppImage on a virtual X display with Chromium sandbox and GPU disabled; no FUSE, physical monitor or hardware-rendering test.",
+    "No Live video, Control input or full Desktop Mode test.",
+    "Nested-desktop journal included gamescope WSI/Vulkan-hook warnings. No warning was dismissed; captured compositor pixels were nonblank.",
+    "Initial CDP response.body() yielded zero bytes despite successful image decode. Repeat verified Content-Length, fresh decoded image, panel selection and PNG export from canvas; the initial raw-body size is not treated as capture failure or proof.",
+    "No private desktop pixels, issue screenshot or raw desktop journal committed."
+  ]
+}

docs/evidence/desktop-capture-packaged-2026-10-24.md

@@ -0,0 +1,100 @@
+# Packaged Desktop Capture, 2026-10-24
+
+Base: `de931bc`. Package: Linux x86_64 **v0.4.17**. Device: real Frame,
+SteamOS **0.5.6**, BUILD_ID **20261015.6141207**. Host: lxso2.
+[Sanitized state and response evidence](desktop-capture-packaged-2026-10-24.json).
+
+## Result and issue boundary
+
+The packaged app discovered the nested KDE compositor and both automated
+Desktop **Capture** button clicks succeeded. The repeat returned HTTP 200,
+`Content-Type: image/png`, `X-Capture-Source: panel`, and Content-Length
+1,209,980. The app decoded a fresh, nonblank 1920×1080 image and displayed
+the Desktop panel badge. No further product failure was reproduced or fixed.
+
+This does **not** establish the full visible-desktop condition in
+[#73](https://github.com/saphid/frame-control/issues/73). `xwininfo` reported
+the desktop window `IsViewable`, and gamescope confirmed focus after
+`vrcmd --showdashboard valve.steam.desktopgame.0`. However, SteamVR still
+reported that overlay `not_visible`. There was no worn-headset visual check.
+The observation proves capture of a mapped nested compositor, not its visible
+presentation to a wearer. Do not close #73 from this evidence.
+
+The issue screenshot shows a desktop panel in the headset view while Desktop
+Capture logs “no app panel is open in the headset.” The reporter used SteamOS
+0.4.5, gave no Frame Control version or reproduction steps, and has not replied
+to the maintainer's 0.4.3 update request. The duplicate page function was already
+fixed; [PR #152](https://github.com/saphid/frame-control/pull/152) subsequently
+improved unknown-state diagnostics. Its [earlier investigation](panel-discovery-2026-10-24.md)
+was blocked from starting a desktop by another task's lock. This run adds a
+current-package capture observation, without reproducing the older failure.
+
+## Procedure
+
+1. Read-only preflight found Game Mode active, full Plasma inactive, Steam and
+   SteamVR running, battery 99%, no nested desktop/runtime and no test lock.
+2. Compared the retained AppImage's SHA-256 with the live v0.4.17 release asset
+   digest: `b1b8eb82bf73a227b2cd36e8f0ef3a2ebdf7967c5853efb08a9634f38227015d`.
+   Extracted an independent copy; `cmp` confirmed its `frame_touch.py` matches
+   the base checkout. No payload was edited.
+3. Started the package's own AppRun, bundled server and Python on Xvfb `:139`
+   with private config/cache/data/profile, telemetry and update checks disabled,
+   and `--no-sandbox --disable-gpu`. Used the existing authorized `ssh frame`
+   identity. T3 preview opened the package server page but does not attach to
+   the existing Electron window. The literal Electron button test used the
+   same Playwright-over-loopback-CDP workflow as the earlier packaged tests.
+4. Acquired `/tmp/frame-test.lock` with atomic `mkdir` and wrote an owner marker.
+   Rechecked no nested runtime or Plasma was present. Started SteamOS's
+   `/usr/bin/steamos-nested-desktop` in the owned transient user unit
+   `fc-issue73-desktop-20261024.service`, using Steam's display/session variables.
+   `RuntimeMaxSec=180s`, `TimeoutStopSec=15s` and `KillMode=control-group` bounded
+   the session. This launches a desktop panel inside Game Mode; no full Desktop
+   Mode switch was sent.
+5. In the actual packaged Electron window, navigated Tools → Capture & Live →
+   Desktop and clicked Capture with `locator.click()`. The first click event
+   recorded `isTrusted=true`. The page selected the KDE compositor on `:0`;
+   the production screenshot path used window `62914560`. Requested the desktop
+   dashboard, read back focus/visibility, and clicked Capture again. Recorded
+   response metadata, fresh decoded image dimensions and canvas pixel range.
+   No direct screenshot API call was substituted for these button clicks.
+6. Ran the packaged `frame_touch.py panels` read-only over SSH to retain its
+   exact discovery result: one focused KDE compositor panel, app ID 0, 1920×1080,
+   display `:0`, with no diagnostic `why` field.
+
+## Cleanup and limits
+
+The owned desktop session ran **09:43:48–09:45:33 UTC** (105 seconds). Hid the
+dashboard to restore its initial hidden state, stopped only the owned unit,
+and verified it was unloaded/inactive with MainPID 0. No Plasma/KWin desktop
+process or nested runtime remained; gamescope's focusable/focused lists were
+empty again. Released only this task's lock, after checking its owner marker.
+
+Delayed readback at **09:46:39 UTC** confirmed the lock absent, Game Mode active,
+full Plasma inactive and the original Steam, vrserver and vrcompositor PIDs
+still running. The Game Mode service invocation was unchanged. Battery was
+99% at cleanup and 100%/Full on the delayed check. Closed both owned preview
+tabs, Electron and Xvfb; their processes and X socket were gone. No test server
+remained. No reboot, installation, security/global setting change or full
+Desktop Mode transition was performed.
+
+The nested desktop journal included gamescope WSI/Vulkan-hook warnings. No
+warning was dismissed. Capture produced nonblank compositor pixels, but this
+run does not assess their usability to a wearer. Private image files stayed
+outside the repository; only state and response metadata are published.
+
+The initial CDP `response.body()` read yielded zero bytes despite successful
+decoding in the page. The repeat verified the PNG Content-Length, fresh image
+dimensions/source/selection and a 2,011,278-byte PNG exported from the canvas.
+The initial raw-body measurement is a harness limitation, not evidence of a
+product capture failure. No Live video, Control input, physical monitor, FUSE
+mounting or hardware rendering was tested. Older SteamOS and other packages
+remain outside this observation.
+
+## Offline verification
+
+`python3 -m unittest discover -s tests -p test_touch.py -v`: **42 tests passed**,
+including the production page's Node panel behavior tests, duplicate-function
+guard, absent versus empty panel diagnostics, alternate displays, capture/input
+target validation and discovery deadlines. JSON parsing and `git diff --check`
+were also checked. No new regression test was added because this is an
+evidence-only change with no reproduced product defect.

docs/evidence/linux-pc-host-lxso2-2026-10-24.md

@@ -0,0 +1,114 @@
+# Linux PC host feasibility on lxso2, 2026-10-24
+
+**Blocked on this host's current desktop environment. No feature enabled and
+no feature PR opened.** Investigation for [issue #23](https://github.com/saphid/frame-control/issues/23),
+starting at `4e45648` (main after #154). This concerns flat desktop panels,
+not Linux PC VR streaming.
+
+## Decision
+
+The smallest useful candidate is one explicitly selected **whole screen**,
+captured through the ScreenCast portal's restricted PipeWire connection,
+encoded locally with GStreamer/x264, and sent to the existing viewer through
+the shared SSH controller. Input, individual windows and virtual displays
+would remain unsupported until separately verified. This candidate was **not
+implemented**: lxso2 currently cannot exercise the real capture permission path.
+
+Development packages could unblock compilation, but would not create a desktop,
+portal backend or consented screen. Synthetic encoding, an Xvfb screen grab or
+using the Frame as its own host would not verify Linux PC desktop capture.
+No host packages or services were changed.
+
+## Evidence
+
+Host: `lxso2`, Linux x86-64, kernel `6.8.0-139-generic`.
+
+- `DISPLAY`, `WAYLAND_DISPLAY` and `XDG_SESSION_TYPE` were unset. The user bus
+  was reachable at `/run/user/1000/bus`.
+- `/run/user/1000/pipewire-0` and `/run/user/1000/wayland-0` did not exist.
+  No processes matched Xorg, Xwayland, Xvfb, GNOME Shell, KWin Wayland, Weston,
+  PipeWire, WirePlumber or xdg-desktop-portal at the process check.
+- D-Bus `ListNames` returned D-Bus, systemd and anonymous connections, with no
+  `org.freedesktop.portal.Desktop`. `ListActivatableNames` also had no desktop
+  portal. These calls queried D-Bus itself without activating capture services.
+- `dpkg-query` found no `xdg-desktop-portal*` or `pipewire*` packages.
+  `libgstreamer1.0-0:amd64` was installed at `1.24.2-1ubuntu0.1`, but
+  `gstreamer1.0-tools` was uninstalled. `gst-launch-1.0` and `gst-inspect-1.0`
+  were absent from PATH. Xvfb was installed, but supplies no portal by itself.
+- `pkg-config --modversion` failed for `gstreamer-1.0`,
+  `gstreamer-app-1.0`, `gstreamer-video-1.0` and `libpipewire-0.3`.
+  `gio-unix-2.0` reported `2.80.0`.
+- `desktop/bundle/pc-host.so` did not exist.
+  `python3 desktop/build.py --with-x264 --out /tmp/frame-linux-pc-feasibility`
+  exited **1** before compilation: required GStreamer pkg-config modules were
+  missing. No native build or encoder runtime success is claimed.
+
+Reproduce the non-activating portal checks in the intended desktop user's
+session, using that session's actual runtime directory and bus:
+
+```sh
+gdbus call --session --dest org.freedesktop.DBus \
+  --object-path /org/freedesktop/DBus --method org.freedesktop.DBus.ListNames
+gdbus call --session --dest org.freedesktop.DBus \
+  --object-path /org/freedesktop/DBus --method org.freedesktop.DBus.ListActivatableNames
+pkg-config --modversion gstreamer-1.0 gstreamer-app-1.0 gstreamer-video-1.0 gio-unix-2.0
+```
+
+## Existing implementation reviewed
+
+- `ui/frame_pcview.py` selects PCView only on Windows and rejects Linux even
+  when enabled. Linux installers do not carry its native bundle.
+- `desktop/portal.c` creates a **RemoteDesktop** session, requests pointer and
+  keyboard devices, and selects monitors and windows (`types=3`). It is not
+  ScreenCast-only or screen-only. Its restricted fd/node and fresh-connection
+  handling are reusable.
+- `ui/frame_pc_agent.py` calls the selection a shared window or screen and
+  picks VA-API when the element is present, falling back to x264. A bounded
+  x264 slice needs explicit encoder policy and unsupported-input behavior;
+  exposing the existing Linux path alone would not meet that scope.
+- `app/main.js` starts Python with the inherited environment; it does not
+  supply a compositor, portal backend or capture permission.
+- `.github/workflows/pc-host.yml` installs native dependencies and tests
+  synthetic x264/protocol behavior with fake capture consent/input. This does
+  not establish interactive Linux desktop capture.
+- Issue #23 and its six existing comments distinguish prior synthetic
+  helper/viewer results from untested Linux desktop capture and consent.
+
+## Verification and limits
+
+`python3 -m unittest discover -s tests -p 'test_pc*.py' -v` exited **0**:
+27 tests ran successfully, with one additional native-class setup skip
+(`native PC libraries not built on this host`). Coverage includes the compiled
+C controller trace, Python adapters, grants and default-off/Windows-only gates.
+It does not prove native GStreamer capture or local-client streaming.
+
+No fake/local native stream, consent prompt, real desktop capture, Frame viewer
+run, benchmark, input or window mode was tested in this investigation. No SSH
+connection to the Frame was needed; no lock was acquired and no headset install,
+launch, stop or settings change was attempted. Issue #113 was left alone.
+No issue comments or other public messages were sent.
+
+## Concrete unblock and next slice
+
+1. Supply an interactive Linux desktop, physical or VM, with a working
+   ScreenCast portal/backend, PipeWire and accessible consent dialog. Installing
+   the portal frontend alone is insufficient. A VM can establish software
+   capture/x264 behavior while physical-host behavior remains unverified.
+2. Install the native dependencies listed in `pc-host.yml` in that environment
+   and build a local `--with-x264` bundle. Resolve x264 distribution
+   licensing/source obligations before shipping it: the current build labels
+   that option test-only and the Windows installer omits it.
+3. Implement a ScreenCast-only session with monitor-only selection, no
+   RemoteDesktop/device request, disabled input in protocol and viewer, hidden
+   window/virtual-display modes, and explicit x264 selection. Preserve the
+   default-off gate and existing Mac/Windows paths.
+4. Verify consent acceptance/refusal/cancellation, Stop/reopen, connection loss
+   and portal closure with a local client decoding actual captured content.
+   Run the shared benchmark and record results without inferring hardware or
+   physical laser behavior.
+5. Only after local capture works, acquire the shared Frame lock once and
+   follow [the headset procedure](../testing.md#headset-smoke-test) for a brief
+   viewer test. If occupied, leave the lock alone and defer device testing.
+
+These are prerequisites and proposed scope, not a ready feature. The Linux
+host request in #23 remains open.

docs/evidence/return-game-mode-packaged-2026-10-24.json

@@ -0,0 +1,226 @@
+{
+  "date_utc": "2026-10-24T09:27:25.354Z",
+  "result": "PASS: literal packaged desktop Return to Game Mode button switched the real Frame from full Plasma; a repeat visible click made no second switch",
+  "documentation_base_commit": "71288d8980040c14f777f0e417f41f7105eaaac4",
+  "host": "lxso2",
+  "steamos_version": "0.5.6",
+  "steamos_build": "20261015.6141207",
+  "prior_evidence": [
+    "https://github.com/saphid/frame-control/issues/142",
+    "https://github.com/saphid/frame-control/pull/143",
+    "https://github.com/saphid/frame-control/pull/156"
+  ],
+  "package": {
+    "tag": "v0.4.17",
+    "asset": "Frame-Control-linux-x86_64.AppImage",
+    "url": "https://github.com/saphid/frame-control/releases/download/v0.4.17/Frame-Control-linux-x86_64.AppImage",
+    "sha256": "b1b8eb82bf73a227b2cd36e8f0ef3a2ebdf7967c5853efb08a9634f38227015d",
+    "verification": "sha256sum matched the live release asset digest. Independently extracted the retained asset into a new private test directory. cmp confirmed bundled frame_backup.py and frame_backup_remote.py equal the checkout versions. No source or payload was changed.",
+    "launch": "--appimage-extract, then squashfs-root/AppRun --no-sandbox --disable-gpu --remote-debugging-port=49372 --remote-debugging-address=127.0.0.1 --user-data-dir=/tmp/frame-return-button-20261024/electron-profile --window-size=1400,950",
+    "display": "Xvfb :138 -screen 0 1440x1000x24 -nolisten tcp; Electron content screenshot 1400x923",
+    "isolation": "Private XDG_CONFIG_HOME, XDG_CACHE_HOME, FRAME_CONTROL_DATA_DIR and Electron profile; FRAME_CONTROL_TELEMETRY=0 and FRAME_CONTROL_NO_UPDATE_CHECK=1. Existing authorized ssh frame identity retained; bundled server and Python used."
+  },
+  "preflight": {
+    "read_only_first": true,
+    "initial_mode": "gamescope-session.target=active; plasma-workspace-wayland.target=inactive",
+    "initial_battery_percent": 99,
+    "initial_battery_status": "Not charging; charger Full",
+    "steam_and_steamvr_running": true,
+    "running_steam_apps": [],
+    "default_login_mode": "game",
+    "lock": "mkdir /tmp/frame-test.lock succeeded atomically; no foreign lock was removed. Initial harmless probe attempt released its own lock, then a fresh atomic acquisition covered both full-session attempts."
+  },
+  "rollback": {
+    "unit": "fc-return-button-rollback-20261024",
+    "probe": "systemd-run --user --unit=fc-return-button-probe-20261024 --on-active=2s --timer-property=AccuracySec=1s --property=Type=oneshot --property=RemainAfterExit=yes /usr/bin/true",
+    "probe_execution": "Result=success\nExecMainStartTimestamp=Sat 2026-10-24 20:27:07 AEDT\nExecMainExitTimestamp=Sat 2026-10-24 20:27:07 AEDT\nExecMainCode=1\nExecMainStatus=0\n",
+    "arm": "systemd-run --user --unit=fc-return-button-rollback-20261024 --on-active=180s --timer-property=AccuracySec=1s /bin/sh -c <guarded command>",
+    "guarded_command": "if [ \"$(systemctl --user is-active gamescope-session.target)\" != active ]; then exec /usr/bin/steamosctl switch-to-game-mode; fi",
+    "verified_before_desktop": "TimersMonotonic={ OnActiveUSec=3min ; next_elapse=1d 21h 53min 49.130174s }\nNextElapseUSecMonotonic=1d 21h 53min 49.130174s\nBindsTo=\nPartOf=\nActiveState=active\nExecStart={ path=/bin/sh ; argv[]=/bin/sh -c if [ \"$(systemctl --user is-active gamescope-session.target)\" != active ]; then exec /usr/bin/steamosctl switch-to-game-mode; fi ; ignore_errors=no ; start_time=[n/a] ; stop_time=[n/a] ; pid=0 ; code=(null) ; status=0/0 }\nBindsTo=\nPartOf=\n",
+    "user_manager_linger": "yes",
+    "desktop_entry": "ssh frame steamosctl switch-to-desktop-mode",
+    "first_click_utc": "2026-10-24T09:27:27.037Z",
+    "cancelled_before_deadline": true,
+    "fired": false,
+    "limit": "The benign transient timer was observed executing. The actual rollback timer configuration was read back, then cancelled after the UI restored Game Mode; its recovery action was not deliberately allowed to fire."
+  },
+  "ui": {
+    "navigation": "Clicked nav Tools, Backup & recovery, and Check in the actual packaged Electron window. Initial Game Mode disabled Return. After full Plasma entry, Check enabled it.",
+    "automation": "Playwright connected to the packaged Electron instance over local CDP and used locator.click() on the visible button; accepted the native JavaScript confirm dialog. No Return API/CLI or production handler was directly invoked by the test. T3 preview was inspected separately and closed; it cannot control this Electron window.",
+    "clicks": [
+      {
+        "isTrusted": true,
+        "utc": "2026-10-24T09:27:27.037Z"
+      },
+      {
+        "isTrusted": true,
+        "utc": "2026-10-24T09:27:32.942Z"
+      }
+    ],
+    "button_bounds_css_pixels": {
+      "x": 47,
+      "y": 709.59375,
+      "width": 156.203125,
+      "height": 44
+    },
+    "confirmation_dialogs": [
+      {
+        "type": "confirm",
+        "message": "Return the headset to Game Mode?\n\nThis closes the desktop and any apps open in it, then starts Steam's Game Mode.",
+        "utc": "2026-10-24T09:27:27.042Z"
+      },
+      {
+        "type": "confirm",
+        "message": "Return the headset to Game Mode?\n\nThis closes the desktop and any apps open in it, then starts Steam's Game Mode.",
+        "utc": "2026-10-24T09:27:32.943Z"
+      }
+    ],
+    "desktop_check": {
+      "http": 200,
+      "body": {
+        "mode": "desktop",
+        "gamescope": true,
+        "plasma": true,
+        "nested_desktop": false,
+        "configured": "gamescope-wayland.desktop",
+        "config_file": "/etc/sddm.conf.d/steamos.conf",
+        "selector": "steamosctl",
+        "session_targets": {
+          "gamescope-session.target": "inactive",
+          "plasma-workspace-wayland.target": "active"
+        },
+        "mode_source": "session-targets"
+      }
+    },
+    "return_responses": [
+      {
+        "http": 200,
+        "body": {
+          "message": "Asked the headset to return to Game Mode; it restarts its session in a few seconds",
+          "state": {
+            "mode": "desktop",
+            "gamescope": true,
+            "plasma": true,
+            "nested_desktop": false,
+            "configured": "gamescope-wayland.desktop",
+            "config_file": "/etc/sddm.conf.d/steamos.conf",
+            "selector": "steamosctl",
+            "session_targets": {
+              "gamescope-session.target": "inactive",
+              "plasma-workspace-wayland.target": "active"
+            },
+            "mode_source": "session-targets"
+          },
+          "switched": true,
+          "command": "steamosctl switch-to-game-mode"
+        },
+        "utc": "2026-10-24T09:27:27.316Z"
+      },
+      {
+        "http": 200,
+        "body": {
+          "message": "The headset is already in Game Mode. The desktop you see is a panel: close it from the Steam dashboard.",
+          "state": {
+            "mode": "game",
+            "gamescope": true,
+            "plasma": false,
+            "nested_desktop": false,
+            "configured": "gamescope-wayland.desktop",
+            "config_file": "/etc/sddm.conf.d/steamos.conf",
+            "selector": "steamosctl",
+            "session_targets": {
+              "gamescope-session.target": "active",
+              "plasma-workspace-wayland.target": "inactive"
+            },
+            "mode_source": "session-targets"
+          },
+          "switched": false
+        },
+        "utc": "2026-10-24T09:27:33.126Z"
+      }
+    ],
+    "final_check": {
+      "http": 200,
+      "body": {
+        "mode": "game",
+        "gamescope": true,
+        "plasma": false,
+        "nested_desktop": false,
+        "configured": "gamescope-wayland.desktop",
+        "config_file": "/etc/sddm.conf.d/steamos.conf",
+        "selector": "steamosctl",
+        "session_targets": {
+          "gamescope-session.target": "active",
+          "plasma-workspace-wayland.target": "inactive"
+        },
+        "mode_source": "session-targets"
+      }
+    },
+    "final_return_disabled": true,
+    "final_text": "Game Mode: the headset is running normally. A desktop you see is a panel; close it from the Steam dashboard.",
+    "screenshots": [
+      "return-game-mode-packaged-2026-10-24-before.png",
+      "return-game-mode-packaged-2026-10-24-after.png"
+    ],
+    "screenshot_scope": "Cropped to the session controls and repeat-action notification; host identity, connection address and backup folder excluded."
+  },
+  "systemd_verification": {
+    "command": "ssh frame systemctl --user show gamescope-session.target plasma-workspace-wayland.target -p Id -p ActiveState -p SubState; ssh frame systemctl --user show gamescope-session.service -p InvocationID",
+    "before": "Id=gamescope-session.target\nActiveState=inactive\nSubState=dead\n\nId=plasma-workspace-wayland.target\nActiveState=active\nSubState=active\nInvocationID=892b843dbe1a4d2ba91b93057bd38463\n295589 /home/steamos/.local/share/Steam/steamrtarm64/steam -silent -vrdisable -deckard\n295066 /opt/steamvr/bin/linuxarm64/vrserver -waitformonitor -ipccontrolfilepath /tmp/SteamVR-IPCControlFile-294978\n",
+    "after_first_click": "Id=gamescope-session.target\nActiveState=active\nSubState=active\n\nId=plasma-workspace-wayland.target\nActiveState=inactive\nSubState=dead\nInvocationID=e8c1085b3bbd4e79a323b3e4a9bc6355\n297506 /opt/steamvr/bin/linuxarm64/vrserver -waitformonitor -ipccontrolfilepath /tmp/SteamVR-IPCControlFile-297420\n",
+    "after_repeat_click": "Id=gamescope-session.target\nActiveState=active\nSubState=active\n\nId=plasma-workspace-wayland.target\nActiveState=inactive\nSubState=dead\nInvocationID=e8c1085b3bbd4e79a323b3e4a9bc6355\n297826 /home/steamos/.local/share/Steam/steamrtarm64/steam -cef-enable-debugging -deckard -gamepadui -steamdeck -steamos3 -vrgamepadui\n297942 /home/steamos/.local/share/Steam/steamrtarm64/steam -child-update-ui -child-update-ui-socket 8 -cef-enable-debugging -deckard -gamepadui -steamdeck -steamos3 -vrgamepadui\n297506 /opt/steamvr/bin/linuxarm64/vrserver -waitformonitor -ipccontrolfilepath /tmp/SteamVR-IPCControlFile-297420\n",
+    "repeat_did_not_restart_game_mode": true,
+    "unchanged_game_service_invocation": "e8c1085b3bbd4e79a323b3e4a9bc6355",
+    "unchanged_steamvr_pid": 297506,
+    "delayed_final_readback_utc": "2026-10-24T09:28:05Z"
+  },
+  "cleanup": {
+    "complete": true,
+    "final_readback": "2026-10-24T09:28:05Z\nId=gamescope-session.target\nActiveState=active\n\nId=plasma-workspace-wayland.target\nActiveState=inactive\nInvocationID=e8c1085b3bbd4e79a323b3e4a9bc6355\nNEXT LEFT LAST PASSED UNIT ACTIVATES\n\n0 timers listed.\nId=fc-return-button-rollback-20261024.timer\nLoadState=not-found\nActiveState=inactive\n\nId=fc-return-button-rollback-20261024.service\nLoadState=not-found\nActiveState=inactive\n\nId=fc-return-button-probe-20261024.timer\nLoadState=not-found\nActiveState=inactive\n\nId=fc-return-button-probe-20261024.service\nLoadState=not-found\nActiveState=inactive\n297826 /home/steamos/.local/share/Steam/steamrtarm64/steam -cef-enable-debugging -deckard -gamepadui -steamdeck -steamos3 -vrgamepadui\n297506 /opt/steamvr/bin/linuxarm64/vrserver -waitformonitor -ipccontrolfilepath /tmp/SteamVR-IPCControlFile-297420\n99\nCharging\ngame\n",
+    "owned_lock_release_exit": 0,
+    "owned_lock_absent": true,
+    "host_processes": {
+      "xvfb": {
+        "pid": 1562020,
+        "exists": false,
+        "cmd": null,
+        "state": null
+      },
+      "electron": {
+        "pid": 1562023,
+        "exists": false,
+        "cmd": null,
+        "state": null
+      },
+      "x_socket_absent": true
+    },
+    "remaining_test_servers": [],
+    "battery_final_percent": 99,
+    "battery_final_status": "Charging",
+    "battery_range_observed_percent": [
+      99,
+      100
+    ],
+    "game_mode_steam_steamvr_running": true,
+    "default_login_mode_after": "game",
+    "headset_installs_or_global_settings_changed": false,
+    "rebooted": false,
+    "notes": "Stopping the timer succeeded. systemctl stop also named its never-started, unloaded service and returned 5; explicit readback confirms both rollback and probe timer/service units are not-found/inactive. No further switch was sent."
+  },
+  "attempts_and_harness_limits": [
+    "Initial harmless timer probe was garbage-collected before its exit metadata could be read. No Desktop Mode switch was attempted. Repeated with RemainAfterExit=yes and verified successful execution.",
+    "First full Plasma attempt clicked the visible packaged Return button and got HTTP 200 / switched=true. The harness then treated absent pgrep matches during the expected session restart as a fatal error. Independent readback confirmed Game Mode and SteamVR had returned. Rollback remained armed until that readback, then was cancelled. This incomplete attempt was not counted as the final pass.",
+    "Final full Plasma attempt tolerated transiently absent Steam/SteamVR while polling systemd targets, passed both trusted visible clicks, and completed the final Check. Stopping the unused rollback service returned unit-not-loaded; explicit subsequent readback verified all four owned probe/rollback units not-found/inactive and zero timers. Cleanup was completed before releasing our lock."
+  ],
+  "limits": [
+    "Unchanged AppImage payload ran after extraction on a virtual X desktop with Chromium sandbox and GPU disabled. FUSE mounting, desktop integration and hardware rendering were not tested.",
+    "Automated trusted pointer clicks in a visible Electron window; no physical-monitor human click or worn-headset visual/interaction assessment.",
+    "Verified only SteamOS 0.5.6 build 20261015.6141207 and the Linux x86_64 v0.4.17 package; older selectors/builds and other desktop platforms remain covered only by their existing tests.",
+    "No release, tag, application code, passwords or security/global settings changed."
+  ],
+  "validation": {
+    "focused_suite": "python3 -m unittest discover -s tests -p test_backup.py -v: 28 tests passed in 2.479s",
+    "json": "python3 -m json.tool: passed",
+    "diff": "git diff --check: passed"
+  }
+}

docs/pc-in-headset.md

@@ -107,6 +107,12 @@ The Linux adapter from #38 (desktop portal, PipeWire, VA-API) is in the tree,
 because it shares `capture.c` and the controller, and CI still builds and tests
 it. The app never offers it and the Linux installers don't include it.
 
+The [2026-10-24 lxso2 feasibility check](evidence/linux-pc-host-lxso2-2026-10-24.md)
+found no running or activatable desktop portal, no PipeWire socket and missing
+native build dependencies. Linux support remains disabled. The evidence records
+the build failure and prerequisites for a screen-only, view-only x264 slice;
+Linux capture, input and window modes have not been verified there.
+
 ## Measuring
 
 The Mac benchmark accepts the PC host:

docs/streaming.md

@@ -7,6 +7,9 @@ This covers three directions, plus input:
 - **C. iPhone → Frame**: mirror the phone inside the headset.
 - **PC VR from Linux**: [feasibility and options](linux-vr-streaming.md),
   including Valve's streaming and USB support. No Linux host tested yet.
+- **Linux desktop → Frame panels**: [PC-host feasibility on lxso2](evidence/linux-pc-host-lxso2-2026-10-24.md).
+  Blocked on missing desktop portal/PipeWire and native build dependencies;
+  Linux desktop capture remains disabled and unverified.
 - **Input**: type and point in the Frame from the Mac or iPhone.
 - **Live view and Control**: watch a panel flat and tap on it to use it.
 
@@ -292,6 +295,10 @@ How (**verified 2026-09-29**, SteamOS 0.4.1, build 20260925.6191901):
   if it persists, report the exact message and SteamOS version. The confirmed
   empty-list advice is retained when the property is present but empty.
   [2026-10-24 investigation and verification limits](evidence/panel-discovery-2026-10-24.md).
+  A later [packaged v0.4.17 test on the real Frame](evidence/desktop-capture-packaged-2026-10-24.md)
+  captured a mapped, focused nested KDE compositor on SteamOS 0.5.6. SteamVR
+  still reported its overlay hidden, so that test does not establish the
+  wearer's visible-desktop condition in #73 or justify closing it.
 - Tested from the iPhone app (Simulator): a tap on the Desktop view focused a
   text box in the panel and the text field typed into it; a trackpad move went
   exactly (+40, +25).

docs/testing.md

@@ -165,6 +165,14 @@ Record the build, actual interaction results, cleanup and any unworn-headset
 limits alongside screenshots or logs. These are caller responsibilities; the
 smoke script below does not acquire this shared lock itself.
 
+[Packaged Desktop Capture evidence, 2026-10-24](evidence/desktop-capture-packaged-2026-10-24.md)
+records v0.4.17 GUI button captures of a real mapped nested desktop on SteamOS
+0.5.6, a bounded owned user unit, and cleanup back to the original Game Mode
+state. Check X window mapping/focus and SteamVR overlay visibility separately:
+successful capture of a mapped window does not prove the desktop is visible
+to a wearer. That run's overlay stayed `not_visible`; #73 remains unverified
+for its reported visible-desktop/0.4.5 condition. Only state/log metadata is public.
+
 ```sh
 scripts/frame-smoke.sh           # needs `ssh frame` to work without a password
 scripts/frame-smoke.sh --pair    # also pairs a throwaway key: approve it in the headset

ui/index.html

@@ -1738,7 +1738,7 @@
         <button class="small" id="sessionCheck">Check</button></div>
       <div class="sub" id="sessionState">Check which mode the headset is in.</div>
       <div class="row" style="margin-top:12px"><button class="small" id="sessionGame" disabled>Return to Game Mode</button></div>
-      <div class="hint">Uses the same switch as Valve's developer tools (<code>steamos-session-select gamescope</code>).
+      <div class="hint">Uses Valve's supported Game Mode switch for this SteamOS build.
         It closes the desktop and anything open in it. If the headset can't be reached, hold Power for 10 seconds to
         restart it; <a href="https://github.com/saphid/frame-control/blob/main/docs/backup-and-recovery.md#stuck-in-desktop-mode" target="_blank">more ways back</a>.</div>
     </section>