Eric Lee / linux-smarc-t335x-v3.2

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Commit 97065e033ec5fd824d0133ecd0c614fe1e5c20bd

Authored by Henrik Rydberg
Committed by Dmitry Torokhov
1 parent d90e6f6aad
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

Input: clarify the no-finger event in multitouch protocol 

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>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Showing 1 changed file with 16 additions and 0 deletions Side-by-side Diff

Documentation/input/multi-touch-protocol.txt
Diff comments   View file @ 97065e0
... ... @@ -68,6 +68,22 @@
68 68 SYN_MT_REPORT
69 69 SYN_REPORT
70 70  
  71 +Here is the sequence after lifting one of the fingers:
  72 +
  73 + ABS_MT_POSITION_X
  74 + ABS_MT_POSITION_Y
  75 + SYN_MT_REPORT
  76 + SYN_REPORT
  77 +
  78 +And here is the sequence after lifting the remaining finger:
  79 +
  80 + SYN_MT_REPORT
  81 + SYN_REPORT
  82 +
  83 +If the driver reports one of BTN_TOUCH or ABS_PRESSURE in addition to the
  84 +ABS_MT events, the last SYN_MT_REPORT event may be omitted. Otherwise, the
  85 +last SYN_REPORT will be dropped by the input core, resulting in no
  86 +zero-finger event reaching userland.
71 87  
72 88 Event Semantics
73 89 ---------------