summaryrefslogtreecommitdiffstats
path: root/kernel/Documentation/input/notifier.txt
diff options
context:
space:
mode:
authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/input/notifier.txt
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/Documentation/input/notifier.txt')
-rw-r--r--kernel/Documentation/input/notifier.txt52
1 files changed, 52 insertions, 0 deletions
diff --git a/kernel/Documentation/input/notifier.txt b/kernel/Documentation/input/notifier.txt
new file mode 100644
index 000000000..95172ca6f
--- /dev/null
+++ b/kernel/Documentation/input/notifier.txt
@@ -0,0 +1,52 @@
+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,&params) == NOTIFY_STOP)
+ || !bound) {
+ notifier_call_chain(KBD_UNBOUND_KEYCODE,&params);
+ return;
+ }
+
+ if (unicode) {
+ param.value = unicode;
+ if (notifier_call_chain(KBD_UNICODE,&params) == NOTIFY_STOP)
+ return;
+ emit unicode;
+ return;
+ }
+
+ params.value = keysym;
+ if (notifier_call_chain(KBD_KEYSYM,&params) == NOTIFY_STOP)
+ return;
+ apply keysym;
+ notifier_call_chain(KBD_POST_KEYSYM,&params);
+}
+
+NOTE: This notifier is usually called from interrupt context.