Configure touchpad double-tap

[John Hupp]

On 2/25/2014 7:00 PM, John Hupp wrote:
> On 2/22/2014 8:24 PM, John Hupp wrote:
>> On 2/20/2014 12:07 PM, John Hupp wrote:
>>> On 2/20/2014 3:05 AM, Ali Linx wrote:
>>>>
>>>> On 02/20/2014 05:26 AM, John Hupp wrote:
>>>>> I just installed Lubuntu Saucy on a Lenovo 3000 laptop and I'm 
>>>>> finding that touchpad double-tap does not seem to work (Synaptics 
>>>>> touchpad).
>>>>>
>>>>> I've seen a few other complaints on related topics but haven't 
>>>>> found anything that really defines what can be configured on 
>>>>> touchpads and how.
>>>>>
>>>>> Options?
>>>>>
>>>> Hi,
>>>>
>>>> AskUbuntu? Ubuntu Forums?
>>>> Try :)
>>>>
>>>
>>> I could have added that one of the posts I saw said that double-tap 
>>> worked fine in Ubuntu, but not in Lubuntu.
>>>
>>> So it would seem that this list ought to be a good place to bring 
>>> this up.
>>>
>>>
>>
>> After further playing around, it seemed that double-tap was not 
>> disabled, but required *VERY* fast tapping.
>>
>> I found synclient, which is installed in Lubuntu Saucy and supposed 
>> to control Synaptics touchpad behavior, with documentation at 
>> http://manpages.ubuntu.com/manpages/saucy/man1/synclient.1.html
>>
>> That documentation indicates that the related config file is at 
>> /etc/X11/xorg.conf, but that doesn't exist on my machine, so at the 
>> moment I don't know what the universal/user configuration locations are.
>>
>> synclient -l reports MaxDoubleTapTime=180 initially, and it allowed 
>> me to set 'synclient MaxDoubleTapTime=360.'  I'm guessing that it 
>> could probably be set as high as 1000.
>>
>> This seemed to help, but double-tap is still unreliable: sometimes it 
>> seems to require unreasonably forceful tapping.
>>
>> synclient also reports settings for:
>>     PressureMotionMinZ
>>     PressureMotionMaxZ
>>     PressureMotionMinFactor
>>     PressureMotionMaxFactor
>> But it is not self-evident to me what behaviors those settings are 
>> supposed to govern and if any of them would set the touchpad to 
>> respond to a lighter touch.
>>
>> I have not yet found any better documentation, and maybe that would 
>> help me achieve better control.  So I'm still open to further help!
>>
>
> I know more now but still don't have a resolution.
>
> Documentation of the settings reported and governed per-session by 
> synclient are at 
> http://manpages.ubuntu.com/manpages/saucy/man4/synaptics.4.html
>
> FingerLow and FingerHigh are the settings that should govern 
> sensitivity, if that is my issue.
>
> Default settings are automatically configured by Xorg, but may be 
> temporarily changed during a session via synclient.  Make permanent 
> changes by editing /usr/share/X11/xorg.conf.d/50-synaptics.conf and 
> adding Options to the existing InputClass section that has the 
> Identifier "touchpad catchall."  An example with Options for FingerLow 
> and FingerHigh:
>
> Section "InputClass"
>     Identifier "touchpad catchall"
>     Driver "synaptics"
>     MatchIsTouchpad "on"
>     MatchDevicePath "/dev/input/event*"
>     Option "FingerLow" "10"
>     Option "FingerHigh" "16"
> EndSection
>
> This laptop is dual-booting Saucy with Windows Vista, and so far I 
> have not been able to configure the touchpad so that it double-taps 
> easily and consistently/reliably the way it does in Windows.  (Which 
> is also to say that I know that the touchpad hardware is OK because it 
> works fine in Windows.)
>

I booted into the *Ubuntu* Live DVD on this laptop, and touchpad 
double-tapping performed very smoothly.

Under Ubuntu, synclient reported different values for VertEdgeScroll and 
HorizTwoFingerScroll than Lubuntu reported, but changing those settings 
to match in Lubuntu did not help the double-tap problem.

I installed Lubuntu Saucy on another laptop, and double-tap worked 
beautifully on that machine, but it has an Alps touchpad rather than 
Synaptics.

I booted into the Lubuntu Trusty 2/14 Daily Build Live DVD on the 
problem laptop and found that it had the same problem with double-tap, 
but while there I discovered that a *TRIPLE-TAP* reliably yielded the 
behavior expected for a double-tap.

So I booted back into Saucy from the hard drive, and found that there 
too, a triple-tap reliably yielded the behavior wanted for a double-tap.

It seems like this information could be used to alter the settings to 
get expected behavior from a double-tap, but I'm not sure how.

Does this tell anyone something?