lkml.org 
[lkml]   [2011]   [Mar]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
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.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2011-03-26 00:33    [from the cache]
©2003-2011 Jasper Spaans