doc: add a short blurb regarding lid switch handling

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

diff --git a/doc/switches.dox b/doc/switches.dox
index 4bb267573fb4533b7fcbf6bcac451a8aba1bc58e..5153dc2e1be9cbec8964c1de8571d2468908a3b5 100644 (file)
--- a/doc/switches.dox
+++ b/doc/switches.dox
@@ -13,4 +13,22 @@ specific features based on a switch state.
 The order of switch events is guaranteed to be correct, i.e., a switch will
 never send consecutive switch on, or switch off, events.
 
+@section switches_lid Lid switch handling
+
+Where available, libinput listens to devices providing a lid switch.
+The evdev event code `EV_SW` `SW_LID` is provided as @ref
+LIBINPUT_SWITCH_LID. If devices with a lid switch have a touchpad device,
+the device is disabled while the lid is logically closed. This is to avoid
+ghost touches that can be caused by interference with touchpads and the
+closed lid. The touchpad is automatically re-enabled whenever the lid is
+openend.
+
+This handling of lid switches is transparent to the user, no notifications
+are sent and the device appears as enabled at all times.
+
+On some devices, the device's lid state does not always reflect the physical
+state and the lid state may report as closed even when the lid is physicall
+open. libinput employs some heuristics to detect user input (specificially
+typing) to re-enable the touchpad on those devices.
+
 */