synaptics bug 31636: non-uniform horizontal and vertical acceleration

[Martin Spacek]

Hello,

About a year ago, Chase Douglas suggested I post about this here. I've only 
recently become annoyed enough to finally do so.

When I add a secondary monitor horizontally to my primary one, my synaptics 
touchpad (on a Thinkpad W510) becomes much more sensitive horizontally than 
vertically. If I add the secondary monitor vertically, it becomes more sensitive 
vertically than horizontally. Others have reported the same issue on different 
machines. Here are the relevant bug reports:

https://bugs.freedesktop.org/show_bug.cgi?id=31636

https://bugs.launchpad.net/xorg-driver-synaptics/+bug/726832

Surely this can't be a design feature, can it? No other input devices (external 
mouse or trackpoint, both via evdev apparently) behave this way, and neither 
does the touchpad in Windows. This essentially breaks the touchpad for me on a 
multi-monitor setup. Fortunately, when plugged into an external monitor, there's 
usually access to an external mouse, which is perhaps why this one has flown 
under the radar for so long. This bug has been around for coming up to a year 
and a half. Could someone maybe have a look at it?

Cheers,

Martin