[PATCH xf86-input-synaptics] Turn down the default sensitivity for MacBook touchpads

[Chase Douglas]

On 06/05/2012 06:35 PM, Peter Hutterer wrote:
> On Tue, Jun 05, 2012 at 09:46:40AM -0700, Chase Douglas wrote:
>> The touchpads are too sensitive by default. A touch is activated when a
>> finger hovers a millimeter off the device. This change turns down the
>> default sensitivity so that accidental touchpad interactions are
>> lessened and pointer interaction accuracy is increased.
>>
>> Signed-off-by: Chase Douglas <chase.douglas at canonical.com>
>> ---
>>  conf/50-synaptics.conf |   10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/conf/50-synaptics.conf b/conf/50-synaptics.conf
>> index 9e86a7a..5b357ea 100644
>> --- a/conf/50-synaptics.conf
>> +++ b/conf/50-synaptics.conf
>> @@ -42,3 +42,13 @@ Section "InputClass"
>>          MatchDriver "synaptics"
>>          Option "SoftButtonAreas" "0 0 0 0 0 0 0 0"
>>  EndSection
>> +
>> +# The trackpads in Apple MacBooks are very sensitive. This input class rule
>> +# turns down the default sensitivity.
>> +Section "InputClass"
>> +	Identifier "MacBook touchpad sensitivity"
>> +	MatchProduct "bcm5974"
>> +	MatchDriver "synaptics"
>> +	Option "FingerLow" "70"
>> +	Option "FingerHigh" "75"
>> +EndSection
>> -- 
>> 1.7.9.5
> 
> what's the pressure sensitivity on those? calculate_tap_hysteresis sets
> those defaults and the calculation is odd to say the least. can we fix this
> to use a sensible calculation?

Pressure is a bit of a misnomer on these devices. It appears to actually
be the width of a touch, even though there is a separate field for the
width, too. It may be that this is the main reason why the current
calculation doesn't work.

I have created two patches that add a new model type and tap hysteresis
calculations for these trackpads. I just hard coded a value, since I
think it will always be equal to this for all bcm5974 devices, and since
it will likely be different from any other devices.

-- Chase