# Re: \[PATCH\] psmouse: Expose drift duration for IBM trackpoints

- From: Dmitry Torokhov \<dmitry.torokhov@gmail.com\>
- Date: 2014-12-17 23:32:03 
- List: linux-input
- Page: https://ratatoskr.run/linux-input/2014/12/8925048
- Thread: https://ratatoskr.run/linux-input/2014/12/8925035/t.md

```text
On Wed, Dec 17, 2014 at 06:09:47PM +0100, haarp wrote:
> Hello,
> 
> IBM Trackpoints have a feature to compensate for drift by
> recalibrating themselves periodically. If for 0.5 seconds
> there is no change in position, it uses this as the new zero.
> 
> This happens often when the trackpoint is in fact being used.
> This is frustrating.
> 
> Raising the time solves the problem.
> IBM's Trackpoint Engineering Specifications offer a
> configuration register for this (rstdft1). It just needs to
> be exposed by the driver, as others already are.
> 
> Cheers!
> -Mike
> 
> 
> IBM Trackpoints have a feature to compensate for drift by recalibrating
> themselves periodically. By default, if for 0.5 seconds there is no change in
> position, it's used as the new zero. This duration is too low. Often, the
> calibration happens when the trackpoint is in fact being used.
> 
> IBM's Trackpoint Engineering Specifications show a configuration register that
> allows changing this duration, rstdft1.
> 
> Expose it via sysfs among the other settings.
> 
> Signed-off-by: Mike Murdoch <redacted>

Applied, thank you.

-- 
Dmitry
```