[PATCH v2 wayland] protocol: spell out that we're using linux/input-event-codes.h button codes

[Peter Hutterer]

Because we already rely on it in the callers anyway. This is a retrofit, which
is not ideal but I'm not sure any compositor out there uses anything else.
Might as well define it.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
This is the button bit only which I think we agreed on so far. I'll do the
key codes in a separate patch.

 protocol/wayland.xml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/protocol/wayland.xml b/protocol/wayland.xml
index 6c6d078..76ffb51 100644
--- a/protocol/wayland.xml
+++ b/protocol/wayland.xml
@@ -1893,6 +1893,14 @@
 	enter event.
         The time argument is a timestamp with millisecond
         granularity, with an undefined base.
+
+	The button is a button code as defined in the Linux kernel's
+	linux/input-event-codes.h header file, e.g. BTN_LEFT.
+
+	Any 16-bit button code value is reserved for future additions to the
+	kernel's event code list. All other button codes above 0xFFFF are
+	currently undefined but may be used in future versions of this
+	protocol.
       </description>
 
       <arg name="serial" type="uint" summary="serial number of the button event"/>
-- 
2.9.3