weston-init: skip socket wait without a display

The previous socket wait fixed a race where the login prompt could appear
before Weston had created its Wayland socket. In that case, logging in as
root left WAYLAND_DISPLAY empty and applications could not use waylandsink.

Only wait for the socket when a DRM display is connected, or when the kernel
does not expose DRM connector status files. This keeps the race fix for
display boots while allowing immediate headless logins.
Keep showing a warning when there is no wayland socket.

https://onedigi.atlassian.net/browse/DEL-10141

Signed-off-by: Isaac Hermida <isaac.hermida@digi.com>

meta-digi-arm/dynamic-layers/stm-st-stm32mp/recipes-graphics/wayland/weston-init/weston_profile.sh

@@ -1,4 +1,38 @@
-if [ "$USER" == "root" ]; then
+find_wayland_display()
+{
+    if [ -e "$XDG_RUNTIME_DIR/wayland-0" ]; then
+        export WAYLAND_DISPLAY=wayland-0
+        return 0
+    fi
+
+    if [ -e "$XDG_RUNTIME_DIR/wayland-1" ]; then
+        export WAYLAND_DISPLAY=wayland-1
+        return 0
+    fi
+
+    return 1
+}
+
+has_connected_drm_display()
+{
+    local drm_status
+    local drm_status_found=false
+    local drm_state
+
+    for drm_status in /sys/class/drm/card*-*/status; do
+        [ -e "$drm_status" ] || continue
+
+        drm_status_found=true
+        read -r drm_state < "$drm_status" || continue
+        if [ "$drm_state" = "connected" ]; then
+            return 0
+        fi
+    done
+
+    [ "$drm_status_found" = "false" ]
+}
+
+if [ "$USER" = "root" ]; then
     export XDG_RUNTIME_DIR=/run/user/`id -u root`
 
     export ELM_ENGINE=wayland_shm
@@ -8,20 +42,16 @@ if [ "$USER" == "root" ]; then
     export PULSE_RUNTIME_PATH=/run/user/`id -u root`/pulse
     export USE_PLAYBIN3=1
 
-    # Wait for 10 seconds until a Wayland socket is available
+    if ! find_wayland_display && has_connected_drm_display; then
+        # Weston may still be creating its socket after the login prompt
+        # appears, but do not delay headless serial logins.
         for i in {1..10}; do
-        if [ -e $XDG_RUNTIME_DIR/wayland-0 ]; then
-            export WAYLAND_DISPLAY=wayland-0
-            break
-        elif [ -e $XDG_RUNTIME_DIR/wayland-1 ]; then
-            export WAYLAND_DISPLAY=wayland-1
-            break
-        else
             sleep 1
-        fi
+            find_wayland_display && break
         done
-
-    if [ -z "$WAYLAND_DISPLAY" ]; then
-        echo "WARNING: No Wayland socket found"
     fi
+    [ -z "$WAYLAND_DISPLAY" ] && echo "WARNING: No Wayland socket found"
 fi
+
+unset -f find_wayland_display
+unset -f has_connected_drm_display