Re: [PATCH] appletouch: Improved finger detection

[Jeremy Huddleston <jeremyhu@freedesktop.org>]

Dmitry Torokhov wrote:
> HI Jeremy,
> 
> On Tue, May 05, 2009 at 12:10:34PM -0700, Jeremy Huddleston wrote:
>> The appletouch driver is prone to reporting multiple fingers when only  
>> one is
>> pressing.  The appletouch driver queries an array of pressure sensors  
>> and
>> counts local maxima in pressure to determine the number of fingers.  It 
>> just
>> does this on the raw values, so a data stream like:
>>
>> 0 100 250 300 299 300 250 100 0
>>
>> actually registers as 2 fingers.
>>
>> This patch updates the logic to ignore small dips in pressure that are  
>> less
>> than the threshold.
>>
> 
> Does it still detect 2 fingers as 2 fingers when they are held together?
> 

Yes... and 3 when 3 are there.  Before, it would frequently report 3
instead of 2 or 2 instead of 1.  I have found the behavior with this
patch very reliable... the old behavior was not reliable for me (perhaps
due to a precision issue in hardware... or a dent in my finger).