2.6.25-rc7

 Documentation

 input

diff --git a/Documentation/input/notifier.txt b/Documentation/input/notifier.txt
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+Keyboard notifier
+
+One can use register_keyboard_notifier to get called back on keyboard
+events (see kbd_keycode() function for details).  The passed structure is
+keyboard_notifier_param:
+
+- 'vc' always provide the VC for which the keyboard event applies;
+- 'down' is 1 for a key press event, 0 for a key release;
+- 'shift' is the current modifier state, mask bit indexes are KG_*;
+- 'value' depends on the type of event.
+
+- KBD_KEYCODE events are always sent before other events, value is the keycode.
+- KBD_UNBOUND_KEYCODE events are sent if the keycode is not bound to a keysym.
+  value is the keycode.
+- KBD_UNICODE events are sent if the keycode -> keysym translation produced a
+  unicode character. value is the unicode value.
+- KBD_KEYSYM events are sent if the keycode -> keysym translation produced a
+  non-unicode character. value is the keysym.
+- KBD_POST_KEYSYM events are sent after the treatment of non-unicode keysyms.
+  That permits one to inspect the resulting LEDs for instance.
+
+For each kind of event but the last, the callback may return NOTIFY_STOP in
+order to "eat" the event: the notify loop is stopped and the keyboard event is
+dropped.
+
+In a rough C snippet, we have:
+
+kbd_keycode(keycode) {
+   ...
+   params.value = keycode;
+   if (notifier_call_chain(KBD_KEYCODE,¶ms) == NOTIFY_STOP)
+       || !bound) {
+      notifier_call_chain(KBD_UNBOUND_KEYCODE,¶ms);
+      return;
+   }
+
+   if (unicode) {
+      param.value = unicode;
+      if (notifier_call_chain(KBD_UNICODE,¶ms) == NOTIFY_STOP)
+         return;
+      emit unicode;
+      return;
+   }
+
+   params.value = keysym;
+   if (notifier_call_chain(KBD_KEYSYM,¶ms) == NOTIFY_STOP)
+      return;
+   apply keysym;
+   notifier_call_chain(KBD_POST_KEYSYM,¶ms);
+}
+
+NOTE: This notifier is usually called from interrupt context.