The desktop uses the client's own game entries; a steam shim hands them to the app

The client already writes one menu entry per installed game (steam steam://rungameid/<id>, with
the game's icon); they were dead for want of a steam command, and r45 added a second entry per
game beside them. Now: steam on the desktop is a shim that hands off to bannerlator-steam-launch
(and is the client itself anywhere else), and bannerlator-desktop-games writes an entry only for
a game the client wrote none for.

README.md

@@ -188,12 +188,12 @@ assets internal. ⚠️ Built; not yet seen installing to a card.
 
 ### The client's games on the desktop
 
-The desktop's menu lists every game the Steam client has installed (Games category, the game's
-own artwork), and the home folder has **Steam Games** and **SD Games** links to their files. A
-game entry - and the menu's **Steam** / **Steam Big Picture** entries - cannot run the client on
-the desktop, where nothing can draw with Vulkan; they hand off to the app
-(`bannerlator-steam-launch`), which ends the desktop session and starts a Steam session in its
-place: the client's **desktop UI** under gamescope, and the game straight away when one was
+The Steam client writes a menu entry for every game it installs (Games category, the game's
+icon), and the home folder has **Steam Games** and **SD Games** links to their files. Those
+entries run `steam steam://rungameid/…`; on this desktop `steam` is a shim, because the client
+cannot run where nothing can draw with Vulkan. It - and the menu's **Steam** / **Steam Big
+Picture** entries - hand off to the app (`bannerlator-steam-launch`), which ends the desktop
+session and starts a Steam session in its place: the client's **desktop UI** under gamescope, and the game straight away when one was
 chosen. Back opens the drawer as in any session; Stop session returns to the app. The list is
 rebuilt at every desktop start. ⚠️ Built; not yet tried on a device.
 

app/src/main/java/com/steamdeck/launcher/session/SessionFiles.kt

@@ -36,6 +36,7 @@ object SessionFiles {
             "usr/local/bin/bannerlator-netmanager" to "usr/local/bin/bannerlator-netmanager",
             "usr/local/bin/bannerlator-steam-launch" to "usr/local/bin/bannerlator-steam-launch",
             "usr/local/bin/bannerlator-desktop-games" to "usr/local/bin/bannerlator-desktop-games",
+            "usr/local/bin/bannerlator-steam-shim" to "usr/local/bin/bannerlator-steam-shim",
         )
         // The desktop's launcher and labwc defaults, only where the desktop package is installed:
         // staging them into a runtime without it would make the desktop look present when it is not.

tools/linuxfs/desktop/steamdeck-desktop

@@ -81,7 +81,9 @@ if [ ! -f /var/cache/fontconfig/.steamdeck-built ] && command -v fc-cache >/dev/
 fi
 # The menu's "Steam" / "Steam Big Picture" entries and one entry per installed game: all of them
 # hand off to the app (bannerlator-steam-launch), since the client cannot draw on this desktop.
+export BL_DESKTOP=1
 ln -sf /usr/local/bin/bannerlator-steam-launch /usr/local/bin/steamdeck-steam 2>/dev/null
+ln -sf /usr/local/bin/bannerlator-steam-shim /usr/local/bin/steam 2>/dev/null
 python3 /usr/local/bin/bannerlator-desktop-games 2>&1 | sed 's/^/[games] /'
 
 echo "== steamdeck-desktop: labwc ($WLR_RENDERER) on $WAYLAND_DISPLAY"

tools/linuxfs/overlay/usr/local/bin/bannerlator-desktop-games

@@ -1,7 +1,8 @@
 #!/usr/bin/python3
-# The client's installed games, on the desktop: one menu entry per game (Games category), which
-# starts it through bannerlator-steam-launch in Steam's desktop UI under gamescope, and two links
-# in the home folder to the game files themselves. Run at every desktop start; stale entries go.
+# The client's installed games, on the desktop. The client writes a menu entry per game itself
+# (`steam steam://rungameid/<id>`, with the game's icon), which the desktop's `steam` shim hands to
+# the app - so an entry of ours exists only for a game the client wrote none for. Plus two links in
+# the home folder to the game files. Run at every desktop start; stale entries go.
 #
 #   bannerlator-desktop-games [steam root]
 import os
@@ -54,12 +55,32 @@ def icon_for(appid):
     return "steam"
 
 
+def client_entries():
+    """App ids the client already wrote a menu entry for."""
+    found = set()
+    if not os.path.isdir(APPS_DIR):
+        return found
+    for entry in os.listdir(APPS_DIR):
+        if entry.startswith(PREFIX) or not entry.endswith(".desktop"):
+            continue
+        try:
+            with open(os.path.join(APPS_DIR, entry), encoding="utf-8", errors="replace") as f:
+                m = re.search(r"steam://rungameid/(\d+)", f.read())
+        except OSError:
+            continue
+        if m:
+            found.add(int(m.group(1)))
+    return found
+
+
 def write_entries():
     os.makedirs(APPS_DIR, exist_ok=True)
     wanted = {}
+    theirs = client_entries()
     for library, _ in LIBRARIES:
         for appid, name in games(library):
-            wanted.setdefault(appid, name)
+            if appid not in theirs:
+                wanted.setdefault(appid, name)
     for entry in os.listdir(APPS_DIR):
         if entry.startswith(PREFIX) and entry.endswith(".desktop"):
             appid = entry[len(PREFIX):-len(".desktop")]
@@ -102,7 +123,8 @@ def link_libraries():
 def main():
     wanted = write_entries()
     link_libraries()
-    print("bannerlator-desktop-games: %d game(s) on the desktop menu" % len(wanted))
+    print("bannerlator-desktop-games: %d entr%s of ours, %d the client's" % (
+        len(wanted), "y" if len(wanted) == 1 else "ies", len(client_entries())))
 
 
 if __name__ == "__main__":

tools/linuxfs/overlay/usr/local/bin/bannerlator-steam-shim

@@ -0,0 +1,12 @@
+#!/bin/bash
+# `steam` on the desktop. The client writes a menu entry per installed game that runs
+# `steam steam://rungameid/<id>`, and its own launchers say `steam`; neither can run the client
+# here (no dma-buf on the desktop), so on the desktop this hands off to the app for a Steam session
+# in the client's desktop UI under gamescope. Anywhere else it is the client itself.
+set -u
+if [ "${BL_DESKTOP:-}" = 1 ]; then
+  url=
+  for arg in "$@"; do case $arg in steam://*) url=$arg ;; esac; done
+  exec /usr/local/bin/bannerlator-steam-launch desktop ${url:+"$url"}
+fi
+exec "${HOME:-/root}/.local/share/Steam/steamrtarm64/steam" "$@"