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.

One problem remained though:

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 I’ve 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 fix my issue.

Damn! I started googling again and found this document I’ve started reading 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!

it. They give too many problems.

Pretty much I couldn’t do anything that required heavy CPU load.

without option to move it. Those are not wise decisions IMHO.