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| -rw-r--r-- | Documentation/input/event-codes.rst | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst index b24ae7d292cc..8741d390b184 100644 --- a/Documentation/input/event-codes.rst +++ b/Documentation/input/event-codes.rst @@ -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: |