For some time I’ve been struggling to get my laptop (Samsung r540)1 to work properly under linux for some time. Eventually I’ve resolved most of my problems2 by installing Ubuntu Oneiric which is pretty nice, except some Unity mis-designs3 which I was able to resolve. But one problem remained: my touchpad wasn’t acting while using the “Two Finger Scroll” feature like it should. The scrolling itself was working, but whenever I reached one of the touchpad borders (which I did pretty much all the time) the document or web page I was viewing (and scrolling) would jump all the way to the top or bottom and lock the whole touchpad for a while. This was pretty annoying, since I use my touchpad (and thus, scrolling) really frequently.
I was able to fix this in Archlinux by enabling SHMConfig option in my xorg.conf, but it seems that Ubuntu don’t accept manual X11 configuration. When I configured X11, like I did under my Arch installation (which meant copying the .conf file), the hell broke and I lost correct screen configuration and my laptop keyboard wasn’t detected.
I’ve begun googling around and discovered that I still can configure my touchpad through the xinput tool. Yeah! I quickly applied what I was doing in Arch through X11 config file, only to discover that it didn’t fixed my issue.
Damn! I started googling again and found this document. I’ve read it and I discovered interesting thing:
When conventional coasting is enabled, horizontal/vertical scrolling can continue after the finger is released from the lower/right edge of the touchpad.
Wait, “finger is released from the lower edge of the touchpad”. This is what I was doing: I would release my fingers after I reached bottom of the touchpad and then the scrolling would broke.
That would mean that I had problem with coasting! Quick search in the document gave me solution how to configure/disable coasting. And since I didn’t like the idea of the scrolling continuation after I released my fingers I decided that I would disable the whole thing. I’ve run
xinput --set-prop "ETPS/2 Elantech Touchpad" "Synaptics Coasting Speed" 0 0
disabling coasting and discovered that everything was working like it should!
Ok, but this was only a one-shot solution. How could I make it permanent? Let’s put a script that does this in /etc/init.d and enable it by running update-rc.d FOO defaults where FOO is the script name. Now everything works as it should!
1 Don’t buy it. Don’t buy any Samsung laptop if you want to run linux on it. They give too many problems.
2 Overheating on Arch, compilation problems and overheating on Gentoo. Pretty much I couldn’t do anything that required heavy CPU load.
3 The whole dashboard thing and dock fixed to the left side of screen without option to move it. Those are not wise decisions IMHO.