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    SubjectRe: [PATCH 1/4] input: Set default events per packet.
    On Fri, Mar 25, 2011 at 1:20 AM, Henrik Rydberg <rydberg@euromail.se> wrote:
    >> +static inline bool is_mt_axis(int axis)
    >> +{
    >> +     return axis == ABS_MT_SLOT ||
    >> +             (axis >= ABS_MT_FIRST && axis <= ABS_MT_LAST);
    >> +}
    >
    > It would be great to get this inline into input/mt.h instead.

    Makes sense. I'll do that.

    >> +     else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit))
    >> +             mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
    >> +                     dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1;
    >
    > This one is a bit iffy - the tracking id is not limited like this in
    > mainline, looks like android usage. A test againts some arbitrary max
    > should do it.

    Yeah, I'm not sure about this one. Tracking ID could effectively have
    any range. All of the MT Protocol A touch screen drivers I have
    looked at, assuming they report tracking ids at all, report a
    reasonable upper bound on the contact points they support.

    Originally, I set an arbitrary maximum bound of 20 slots. In the
    interests of keeping it simple, I decided to remove that bound when I
    submitted the patch for review here.

    How about:

    mt_slots = min(MAX_MT_SLOTS_TO_INFER_FROM_TRACKING_ID_RANGE,
    dev->absinfo[ABS_MT_TRACKING_ID].maximum -
    dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1);

    Where MAX_MT_SLOTS_TO_INFER_FROM_TRACKING_ID_RANGE is set to 32 or something.

    There's also the question of how many slots we should infer when
    neither ABS_MT_SLOT or ABS_MT_TRACKING_ID is available. The drivers
    I've seen that don't provide tracking ids, are very basic and tend to
    only support 2 touch points.

    I guess we could add a DEFAULT_NUMBER_OF_MT_SLOTS constant to handle that case.

    Please feel free to suggest better names for these constants.

    Jeff.
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