Commit 42764f97 authored by Benjamin Tissoires's avatar Benjamin Tissoires Committed by Jiri Kosina
Browse files

Input: docs: add more details on the use of BTN_TOOL 



The HID core stack used to be very relaxed considering the BTN_TOOL_*
usage. With the recent commits, we should now enforce to have only one
tool at a time, meaning that we can now express that requirement in the
docs.

Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: default avatarPing Cheng <ping.cheng@wacom.com>
Acked-by: default avatarPeter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 5c20000a

Documentation/input/event-codes.rst

+5 −1
Original line number Diff line number Diff line
@@ -137,7 +137,11 @@ A few EV_KEY codes have special meanings: 
    code should be set to a value of 1. When the tool is no longer interacting

    with the input device, the BTN_TOOL_<name> code should be reset to 0. All

    trackpads, tablets, and touchscreens should use at least one BTN_TOOL_<name>

    code when events are generated.

    code when events are generated. Likewise all trackpads, tablets, and

    touchscreens should export only one BTN_TOOL_<name> at a time. To not break

    existing userspace, it is recommended to not switch tool in one EV_SYN frame

    but first emitting the old BTN_TOOL_<name> at 0, then emit one SYN_REPORT

    and then set the new BTN_TOOL_<name> at 1.



* BTN_TOUCH: