Configure touchpad double-tap

Wed May 7 21:02:17 UTC 2014

On 2/28/2014 5:28 PM, John Hupp wrote:
> On 2/27/2014 8:10 PM, John Hupp wrote:
>> On 2/26/2014 6:41 PM, John Hupp wrote:
>>> 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?
>>>
>>
>> It seems to me like this behavior is a bug, probably related to Xorg, 
>> or more likely LXDE since it does not occur under Ubuntu.
>>
>> I like the idea that Trusty is a bug-fix-oriented release, and I'd 
>> like to see what I can do to help get this fixed for Trusty as well 
>> as Saucy.
>>
>> I've been reading https://wiki.ubuntu.com/Lubuntu/Testing/ and linked 
>> docs.  It seems like I would be required to join a QA team in order 
>> to do anything (e.g. access the QA mail list), even if my focus were 
>> fixing one problem.  Then I read about laptop testing, and it seemed 
>> that one would have to join a laptop testing team that was 
>> Ubuntu-oriented rather than focused on Lubuntu, and the job 
>> description also seems focused on execution of prescribed test cases.
>>
>> I should say that I also have an interest in certain other bug-fixes 
>> for Trusty -- most of them for the desktop -- but admitting my 
>> immediate interest in this specific laptop problem, does anyone have 
>> advice on how to proceed?
>>
>> One late, parting thought: Instead of joining a QA team, etc., can I 
>> file a standard bug report at Launchpad for issues with Trusty?
>>
>
> OK, without knowing for sure if this was the best way to proceed, I 
> filed a bug report for Saucy at 
> https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1286326 
> and for Trusty at 
> https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1286372
>
> In both cases I filed against xserver-xorg-input-synaptics, even while 
> wondering why the same package would work under Ubuntu but not Lubuntu.
>
>

It seems that the synclient MaxDoubleTapTime setting (or setting 
MaxDoubleTapTime in /usr/share/X11/xorg.conf.d\50-synaptics.conf) does 
not govern the Synaptics touchpad double-tap.

Instead, it is responding to a GTK2 setting, in which the default 
double-tap time is 250 ms.

To change that per-user (and there is probably a global setting 
somewhere -- wish I knew where), create ~/.gtkrc-2.0 with content like:
        gtk-double-click-time=400
though values up to 1000 are sometimes suggested.

Sources: http://forum.lxde.org/viewtopic.php?f=8&t=501 and 
https://help.ubuntu.com/community/Lubuntu/Mouse