Re: [PATCH v3 12/13] HID: introduce Scan Time

From: Dmitry Torokhov
Date: Fri Nov 09 2012 - 03:45:22 EST


Hi Benjamin,

On Wed, Nov 07, 2012 at 05:37:35PM +0100, Benjamin Tissoires wrote:
> Win 8 digitizer devices provides the actual scan time computed by the
> hardware itself. The value is global to the frame and is not specific
> to the multitouch protocol (though only touch, not pen, should use it
> according to the specification).
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx>
> ---
> Documentation/input/event-codes.txt | 9 +++++++++
> drivers/hid/hid-input.c | 4 ++++
> include/linux/hid.h | 1 +
> include/linux/input.h | 1 +
> 4 files changed, 15 insertions(+)
>
> diff --git a/Documentation/input/event-codes.txt b/Documentation/input/event-codes.txt
> index 53305bd..80c06e5 100644
> --- a/Documentation/input/event-codes.txt
> +++ b/Documentation/input/event-codes.txt
> @@ -174,6 +174,15 @@ A few EV_ABS codes have special meanings:
> the input device may be used freely in three dimensions, consider ABS_Z
> instead.
>
> +* ABS_SCAN_TIME:
> + - Used to report the number of microseconds since the last reset. This event
> + should be coded as an uint32 value, which is allowed to wrap around with
> + no special consequence. It is assumed that the time difference between two
> + consecutive events is reliable on a reasonable time scale (hours).
> + A reset to zero can happen, in which case the time since the last event is
> + unknown. If the device does not provide this information, the driver must
> + not provide it to the user space.
> +

This should not be an absolute event but rather EV_MSC/MSC_TIMESTAMP.

Thanks.

--
Dmitry
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