Media keys working again

README.md

@@ -78,7 +78,14 @@ Supported languages: German, English, Spanish, French.
 
 The footer of the window shows the daemon state (`Daemon: running · Device: …`
 plus the last G key that fired, or `Daemon: not reachable`) and follows it live:
-start or stop the daemon while the GUI is open and the line updates itself.
+start or stop the daemon while the GUI is open and the line updates itself. Two
+more states are reported explicitly: `Device: not found` (the daemon is up but
+has no keyboard) and `Configuration error` (a reload failed, so the daemon kept
+the mappings it had).
+
+The window starts from the saved mappings: it loads
+`~/.config/gKeyMapper/mappings.conf` when it opens, so `Save mappings` in a fresh
+window rewrites the same content instead of emptying the file.
 
 ## Running the daemon
 
@@ -95,9 +102,12 @@ The daemon reads G1–G9 from the keyboard and replays the configured action
   `make install` ships a udev rule (`TAG+="uaccess"`) for that. On Linux Mint the
   device already has such an ACL, otherwise install the rule or add your user to
   the `input`/`uinput` group.
-- While it runs, the kernel driver is detached from the vendor interface, so the
-  media keys (mute / volume / play) may stop working until it exits — it
-  reattaches the driver on shutdown.
+- The media keys (mute / volume / play / next / previous / stop) keep working
+  while it runs. The keyboard delivers them on the vendor interface — as a second
+  kernel input device (`…/input1`, the "… G910 Keyboard" consumer device) when the
+  daemon is *not* running — so the daemon picks those reports up and forwards them
+  unchanged through its virtual keyboard. There is nothing to configure; they
+  behave exactly as they do without the daemon.
 - The mappings file is **watched**: save in the GUI and the daemon picks the
   change up by itself (within about half a second), no restart and no signal.
   `SIGHUP`/`SIGUSR1` reload it on demand, which is also the fallback on systems
@@ -110,7 +120,15 @@ The daemon reads G1–G9 from the keyboard and replays the configured action
   Note: the kernel truncates the process name to 15 characters, so
   `pgrep -x gkeymapper-daemon` does **not** match.
 - A failed reload keeps the previous mappings, so a transient read error never
-  silently disables every key.
+  silently disables every key. The GUI shows it as `Configuration error` in the
+  footer.
+- It does **not** need the keyboard to be present: when it is unplugged (or not
+  there yet when the session starts) the daemon keeps running, reports
+  `Device: not found` and looks for it again every 2 s. A re-plug needs no
+  restart and keeps the GUI connection.
+- A G key fires when its report first shows it as pressed: holding it down does
+  not repeat the action, and two G keys held at once both fire (the report
+  carries the state of all nine keys, not one key per report).
 - Only one instance may run: a second one prints why it cannot get the bus name
   and exits, instead of fighting over the keyboard and creating a second virtual
   keyboard.
@@ -123,6 +141,14 @@ The daemon reads G1–G9 from the keyboard and replays the configured action
   layout.
 - `command:...` is run through the shell, so arguments work
   (`command:/usr/bin/firefox --new-window`); a plain program path is also fine.
+  It inherits the environment of the user service, i.e. of your desktop session —
+  `DISPLAY`, `XAUTHORITY` and `PATH` are already there on a normal setup. If a
+  command cannot reach the display, export them into the user manager:
+
+  ```bash
+  systemctl --user import-environment DISPLAY WAYLAND_DISPLAY XAUTHORITY
+  systemctl --user show-environment | grep DISPLAY
+  ```
 
 Stop it with Ctrl+C or `kill`; it reattaches the kernel driver on the way out.
 
@@ -294,7 +320,10 @@ export PKG_CONFIG_PATH=/usr/lib/x86_64-linux-gnu/pkgconfig:/usr/share/pkgconfig:
 
 ## Planned next steps
 
-- Support the media keys and the M1–M3 / MR keys of the G910.
+- Make the media keys remappable (they are forwarded unchanged today, see above)
+  and support the M1–M3 / MR keys of the G910.
+- `typeout`: type out a fixed text, like the reference project's action of that
+  name (the daemon would resolve the text through the active layout).
 - Profiles: swap mapping sets on the fly (the G910's M keys), which is what the
   reserved `SetProfile` D-Bus method was meant for.
 - Key sequence timing: per-step delays for recorded macros.