[ltp] Changing sensitivity ThinkPad USB Keyboard with TrackPoint

Richard Neill linux-thinkpad@linux-thinkpad.org
Wed, 16 May 2012 12:58:41 +0100

> Just to make sure: You did try to configure it using xinput, right?
> e.g.
> $ xinput list
> Virtual core pointer
> ...
> TPPS/2 IBM TrackPoint
> $ xinput list-props 'TPPS/2 IBM TrackPoint'
> [lots of interesting stuff to tweak]

Yes, I did. Xinput allows for the X-server to tweak things once the 
signal reaches it. This allows for middle-button as emulate-wheel, and 
horizontal scrolling. But the trackpoint "pre-amp" gain is actually 
controlled in the hardware itself, and requires writing commands back to 
the keyboard.

For a Thinkpad, this is:
	echo -n 255 > /sys/devices/platform/i8042/serio1/sensitivity

For the older USB keyboards, there is no way to do it (as yet)

For the new USB keyboard, the tpkbdctl program works.

[It's possible to fake it slightly using mouse-speed and acceleration, 
but this reduces fine-control. Turning up the analog gain is better]