[ltp] Hacking the UltraNav USB keyboard

[Richard Neill]

> Does anyone have any thoughts?
> 
> I think most USB devices are still PS/2 compliant, because you can just 
> stick a USB-PS/2 adapter on them and they will work. I don't think there 
> is anything in PS/2 which will let you specify things like sensitivity 
> so I would have thought it would all be done in software.

Pretty sure this one isn't - it's a combined
   keyboard/trackpoint/touchpad/2-port usb-hub device.

> 
> Besides- there isn't really any point in doing it in hardware- why make 
> extra work for yourself? All you'd be doing is scaling the output, which 
> might as well be done in software.

The reason why I expect it to be hardware related is that there is a 
large number of features provided. There are about 10 different 
sensitivity/rate/inertia/negative-intertia parameters, as well as 
options for press-to-select and the like.

Very old thinkpads (eg A22 and before) have the trackpoint emulate a PS2 
mouse. But the kernel provides an extra interface to the trackpoint, 
either in /sys, or via tp4d (kernel 2.4).

Newer thinkpads (with a pad as well as a stick), and the USB Ultranav 
use a synaptics device, which is quite sophisticated. I'd expect that to 
have support for various modes of the daisy-chained trackpoint.

Richard