Messages in this thread Patch in this message | | | From | "Henrik Rydberg" <> | Subject | [PATCH] input: mt: clarify the no-finger event | Date | Sat, 20 Mar 2010 23:18:06 +0100 |
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The current documentation does not explicitly specify how to report zero fingers, leaving a potential problem in the driver implementations and giving no parsing directive to userland. This patch defines two equally valid ways.
Signed-off-by: Henrik Rydberg <rydberg@euromail.se> --- Documentation/input/multi-touch-protocol.txt | 16 ++++++++++++++++ 1 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/Documentation/input/multi-touch-protocol.txt b/Documentation/input/multi-touch-protocol.txt index 8490480..eacb226 100644 --- a/Documentation/input/multi-touch-protocol.txt +++ b/Documentation/input/multi-touch-protocol.txt @@ -68,6 +68,22 @@ like: SYN_MT_REPORT SYN_REPORT +Here is the sequence after lifting one of the fingers: + + ABS_MT_POSITION_X + ABS_MT_POSITION_Y + SYN_MT_REPORT + SYN_REPORT + +And here is the sequence after lifting the remaining finger: + + SYN_MT_REPORT + SYN_REPORT + +If the driver reports one of BTN_TOUCH or ABS_PRESSURE in addition to the +ABS_MT events, the last SYN_MT_REPORT event may be omitted. Otherwise, the +last SYN_REPORT will be dropped by the input core, resulting in no +zero-finger event reaching userland. Event Semantics --------------- -- 1.6.3.3
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