Touchpad accel, spirals and xset

Paul Fox pgf at laptop.org
Thu Jan 21 08:50:01 EST 2010


james wrote:
 > One thing I realised I could have emphasised is that the attempted
 > recalibration based on jumpiness is self perpetuating. Much like why
 > post_interrupt_delay didn't work. We're trying to think of things the device
 > developers would have already thought about.

very true -- the goal of all the recent generations of that
driver has been to figure out when its safe to recalibrate (as
well as when it's necessary).  the new driver does a better
job of that than the "old" driver, but if someone is insistent
on having two fingers on the touchpad, or whatever, we'll almost
certainly recalibrate at the wrong moment.

 > 
 > > I can't think of a way to know when it is safe to recalibrate.
 > 
 > That is where I explained what was described as "spew", being helpful.
 > 
 > I just fired up the tech
 > specs<http://wiki.laptop.org/go/Image:KGDMFA001-non-confidential.pdf>(the
 > xo displays it correctly), and page 14 has the point about auto self
 > recalibration...
 > 
 > ---
 > 7) Automatic calibration setting command Enable/Disable       *C ver
 > 
 >    This command sets whether to do the calibration automatically when the
 > following states are generated.
 >    a. The high-speed operation not generated in the normal operation when
 > continuing.
 >    b. When you continuously generate the same position for ten seconds or
 > more.
 > ----
 > 
 > For (b), 10 seconds is a long time.

right.  too long to let the pad sit and spew.  is that what you mean?

 > But does anyone know about (a),

yes, that's a good question.  i think i used to understand it as referring
to a failed driver-induced switch from 3-byte to 6-byte mode, but i may
be misremembering.  richard may remember better.

 > and if/why we do/dont use auto calib without
 > the firmware module recalibs?

i don't understand your question.

paul
=---------------------
 paul fox, pgf at laptop.org


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