From a9ed3aa9b87ee41e8ab3ff471b1331c154767e45 Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Sat, 26 Sep 2026 07:57:59 +1000 Subject: Merge tag 'drm-misc-fixes-2026-09-24' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-fixes A number of fixes: - bridge: - samsung-dsim: fix GPIO lifetime - client: Null pointer dereference fix - imagination: error handling fix, page handling fix - nouveau: fix reference leaks, double-frees, out-of-bounds accesses, use-after-frees, don't reject config without SCDC, a number of workarounds - virtio: fix memory leak, reference leaks, null pointer dereference, add pixel blend mode, cache coherency fix Signed-off-by: Dave Airlie From: Maxime Ripard Link: https://patch.msgid.link/arU22zzqUGDEco1y@houat --- Documentation/input/notifier.rst | 55 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 Documentation/input/notifier.rst (limited to 'Documentation/input/notifier.rst') diff --git a/Documentation/input/notifier.rst b/Documentation/input/notifier.rst new file mode 100644 index 000000000..824379399 --- /dev/null +++ b/Documentation/input/notifier.rst @@ -0,0 +1,55 @@ +================= +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 (see ): + +- '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_*; +- 'ledstate' is the current LED state; +- '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. -- cgit v1.3.1