doc: add a note that sometimes there's more than one ID_INPUT_* set

Just setting one of them on a device doesn't guarantee that libinput takes
that as device type.

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

diff --git a/doc/device-configuration-via-udev.dox b/doc/device-configuration-via-udev.dox
index fc1c0af8e60112dee587a7e3f69c1cbc03a4f812..c319c409d3d9d822faca5dfcc094f3c064b78f08 100644 (file)
--- a/doc/device-configuration-via-udev.dox
+++ b/doc/device-configuration-via-udev.dox
@@ -44,7 +44,10 @@ udev_device_type.</dt>
 ID_INPUT_TOUCHSCREEN, ID_INPUT_TABLET, ID_INPUT_JOYSTICK,
 ID_INPUT_ACCELEROMETER</dt>
 <dd>If any of the above is set, libinput initializes the device as the given
-type, see @ref udev_device_type.</dd>
+type, see @ref udev_device_type. Note that for historical reasons more than
+one of these may be set at any time, libinput will select only one of these
+to determine the device type. To ensure libinput selects the correct device
+type, only set one of them.</dd>
 <dt>WL_SEAT</dt>
 <dd>Assigns the logical seat for this device. See
 libinput_seat_get_logical_name()