Input: MT - Specify that ABS_MT_SLOT must have a minimum of 0

This is effectively already in force through input_mt_init_slots, and uinput
too ignores the actual minimum.

Since slots are a kernel-genenerated axis only, non-zero minimums make
little sense and are likely to cause errors. Better to treat a non-zero
minimum as kernel bug if it ever happens.

Signed-off-by: Peter Hutterer <[email protected]>
Acked-by: Benjamin Tissoires <[email protected]>
Signed-off-by: Henrik Rydberg <[email protected]>

diff --git a/Documentation/input/multi-touch-protocol.txt b/Documentation/input/multi-touch-protocol.txt
index 2c179613f81b05c5faa952c0b92e3e79cdddd535..de139b18184a16a6a1fdf58d6f3ea50422efa2c7 100644 (file)
--- a/Documentation/input/multi-touch-protocol.txt
+++ b/Documentation/input/multi-touch-protocol.txt
@@ -80,6 +80,8 @@ Userspace can detect that a driver can report more total contacts than slots
 by noting that the largest supported BTN_TOOL_*TAP event is larger than the
 total number of type B slots reported in the absinfo for the ABS_MT_SLOT axis.
 
+The minimum value of the ABS_MT_SLOT axis must be 0.
+
 Protocol Example A
 ------------------