configuring laptop touchpad

29 September 2007 at 7:08 pm (Fedora, Ubuntu, VGN-T250P) (, , )

I have a VGN-T250P laptop with some GNU/Linux distributions that I’m multibooting for a while until I decide which one to keep. First thing after install is to get the touchpad functioning properly so that I can work.

In Ubuntu 7.04 (Feisty Fawn), I used gnome-app-install (Add/Remove Applications) to install gsynaptics (Touchpad). It shows up in System > Preferences. It won’t work yet though; it throws an error: “GSynaptics couldn’t initialize.
You have to set ‘SHMConfig’ ‘true’ in xorg.conf or XF86Config to use GSynaptics”. This is remedied by editing /etc/X11/xorg.conf and adding the line:

Option “SHMConfig” “true”

under the section labeled “Synaptics”. You have to restart the X server then, which can usually be done easily by hitting Ctrl-Alt-Backspace twice. It’s a bit of an annoying irony that you have to manually edit the xorg.conf file to start a program that lets you avoid manually editing the xorg.conf file.

After GNOME’s touchpad configurator was running, the first thing I did was turn off tapping. Horizonal scrolling was off so I turned it on. This is the baseline of usability for me. Next is to deal with Firefox.

Firefox has a bothersome default behavior that many touchpad users complain about. Horizonal scrolling, which can be easily initiated with a casual finger swipe, causes the browser to jump forward and backward through the current page’s history, as though you were clicking on the arrow buttons. From reading the forums I found while troubleshooting, it seems many people misinterpret this and go looking for mouse gestures to turn off.

The solution is to go into about:config and change mousewheel.horizscroll.withnokey.action to either 1 or 0. Gentoo-wiki.com says that 1 enables normal horizontal scrolling, and I’m assuming that 0 disables any functionality. 1 works for me. Most every page I see in google says you also need to toggle mousewheel.horizscroll.withnokey.sysnumlines to true, but I cannot figure out why and it does not seem to make a difference on my system. Mozdev.org implies it’s irrelevant, saying “Scroll by a number of lines equal to system default?”

All the most annoying touchpad behavior is fixed now, but the cursor is still too slow. It does not move far enough across the screen for a quick finger swipe. Unfortunately, this is not as easily remedied as it should be. System > Preferences > Mouse does not seem to have any effect on the cursor speed in Ubuntu, although this method works fine in Fedora 7. The problem seems to be described by bug #118593.

It can be solved using synclient. Check the man page for syntax. I got the results I wanted with these settings: MinSpeed=0.3, MaxSpeed=1, AccelFactor=0.02 (different people’s hardware will need different settings). MaxSpeed must exceed MinSpeed or you get no acceleration. I found the most important setting was AccelFactor. Mine was originally set to approximately 0.006, and though adjusting MaxSpeed didn’t do much, AccelFactor made a big difference.

The changes from synclient are temporary and last only through the current Xorg session. You have to go into /etc/X11/xorg.conf and add the settings that worked for you, to make them permanent.

For Fedora 7, the above instructions can be followed (it’s only superficially different, if at all), except it’s not necessary to bother with synclient. GNOME’s regular mouse config app will work.

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