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    SubjectRe: [PATCH 1/4] Adding documention
    On 08/26/2010 06:54 AM, Rafi Rubin wrote:

    [...]

    > +Parameters

    > +----------
    > +
    > +Note: values set at load time are global and will apply to all applicable
    > +devices. Adjusting parameters with sysfs will override the load time values,
    > +but only for that one device.
    > +
    > +The following parameters are used to configure filters to reduce noise:
    > +
    > +activate_slack number of fingers to ignore before processing events
    > +
    > +activation_height size threshold to activate immediately
    > +activation_width
    > +
    > +min_height size threshold bellow which fingers are ignored
    > +min_width both to decide activation and during activity
    > +
    > +deactivate_slack the number of "no contact" frames to ignore before
    > + propagating the end of activity events
    > +
    > +When the last finger is removed from the device, it sends a number of empty
    > +frames. By holding off on deactivation for a few frames we can tolerate false
    > +erroneous disconnects, where the sensor may mistakenly not detect a finger that
    > +is still present. Thus deactivate_slack addresses problems where a users might
    > +see breaks in lines during drawing, or drop an object during a long drag.


    Without contact tracking, it is hard to imagine activation filtering to work
    properly. I would advocate to remove this functionality from the driver, and add
    it in userspace instead.

    Henrik


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