Touchpad accel, spirals and xset

James Cameron quozl at
Wed Jan 20 22:11:41 EST 2010

On Thu, Jan 21, 2010 at 01:30:06AM +0100, James Zaki wrote:
> The first thing I suspect most people do while waiting for the gui to
> become responsive is try to move the curser.

Yes, I've seen children do that.  Or press keyboard keys hoping it will
go faster booting.  It seems to work for them because their perception
of time is altered by interacting.

> The init of the psmouse module triggers a calibration.

Tested ... holding a finger on the touchpad during boot ... does cause

> To prove, first turn off how the existing module triggers
> recalibrations (I will explain the problem with one of them in a
> moment)
> ---
> cd /sys/module/psmouse/parameters
> echo 0 > jumpy_delay; echo 0 >spew_delay
> ---
> Now give your xo a 5-finger-salut. The regular 4-finger-salut is here
> but just before hitting that final fn key, try rest a finger on the
> touchpad (the nose squished a bit also works too). The bigger the
> touch, the greater areas are miscalibrated.

Reproduced without changing parameters or a nose.

> One way to reproduce was with a finger in one corner tap the other
> corner whilst lifting the first finger. Doing something like this a
> few times (basically triggering the recalibrate by imperfect use) will
> cause the calibration to occur whilst your fingers are there.

Reproduced easily.  (all above 802 on XO-1)

I agree, it does seem that the calibration as a result of jumpiness
might cause symptoms.

I can't think of a way to know when it is safe to recalibrate.

James Cameron

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