multi-touch-dev team mailing list archive

[Rafi Rubin <rafi@xxxxxxxxxxxxxx>]

> > In addition, I'd like to figure out if whatever the n-trig calibtation
> > tool does could be done automatically in the driver or in my X
> > configuration so I don't have to run this every time I reboot the
> > system...
> That's odd... I don't think any of us need to run the calibration tool
> that often. I've never had to run it on my Dell Studio 17, and I think
> Duncan has run it once to fix issues.
I've run it on your studio 17 (just to test the routine, not because it 
was responding poorly), but that's besides the point.
Ray, please confirm the frequency and conditions of your recalibrations. 
  If you have to calibrate on every boot, but its stable for long 
periods during a normal boot then something is definitely very strange 
and I'm going to ask you to collect various samples for analysis.

There are a number of factors which I've specifically seen effect the 
rate of decay.  Off the top of my head:
- device power supply
- grounding
- temperature
- humidity (and ambient static)

I have also suspected imperfect firmware installs might occur, but 
that's a hard one to verify.
You also mentioned having a newer firmware than anyone else has 
reported.  So you may have the honor of discovering new bugs :)
> I think there are many things that could be done to make this easier,
> but it really depends on how bad the problem is :). Our hope was that
> having a tool that *may* need to be run once would be good enough. We
> don't even package it up in Ubuntu proper. However, we may need to look
> into this again.
Releasing the kernel calibration code is still on my todo list.  Once in 
place it will provide a simpler approach.  If you think such a tool is a 
priority, then I'll clean that up and ask you (Chase) to look it over.
> I worry also about auto-calibration. One isn't supposed to touch the
> screen during calibration, and we don't want to flash the screen with
> "HANDS OFF!" every time one boots into Ubuntu :).
This has come up in discussion several times.  I still don't have a sure 
answer to whether the ntrig calibration is incremental/cumulative or if 
it gets completely reset every time you run it.  My experience suggests 
its incremental, in which case contact during a short partial 
calibration would mostly result in a very slight alteration of 
sensitivity and only where the user is touching.  It think there are 
many opportunities to freshen up calibration slightly.  For example, 
when the lid is closed and the machine is either going to sleep or blank 
the screen, or after the machine is idle for a while.
Anyway, that's another conversation.  Incremental calibration is likely 
not relevant if the device is completely messed up on every boot.

Rafi