Touchpad support for ?

Karl Hegbloom hegbloom at
Fri Jun 10 22:36:49 CDT 2005

On Sat, 2005-06-11 at 13:21 +1000, Daniel Stone wrote:
> This is what we do by default on laptops.  I don't see why you want to
> move this from done-by-default to a Debconf question?

I'm sorry; it was not there by default when I installed on my one and
only laptop.  If it's writing a synaptics entry now, and using the
synaptics driver rather than the ps/2 mouse driver for it, then great
work.  Back when I installed this, I had to write it in by hand... in
fact, it was probably an XF86Config originally.

> > With 'SHMConfig' on, GUI and command line tools can change touchpad
> > settings.
> SHMConfig is hideously insecure, and also breaks hard if you have more
> than one X server.  So my mum would be there trying to change the
> touchpad settings on her session, and changing them to extremities
> because it's not working.  Then I'd log back in to my session and find
> my touchpad is unusable.

Why would more than one X server be running on the typical laptop with a

What are the security risks?  Why is it insecure?  I must admit relative
ignorance of how SHMConfig actually works.  I understand that it's using
shared memory, vs some sort of command pipeline.  Isn't access to shared
memory controlled in some way?  Apache uses it, right?  I promise to
read W.R. Stevens fairly soon...  a pristine copy is on my shelf glaring
at me even as I type this.

Do you think there's a way to make it more secure, so that it would be
safe to enable it, or a revised incarnation of something like it?

> > There is also a daemon that turns the touchpad off until 1
> > second after the last keystroke.  That prevents pointer taps from thumbs
> > hitting the pad while typing.
> If this relies on SHMConfig, see above.

It does.

In honesty, I wish they'd stop making touchpads.  I hate them.  I always
carry a USB mouse for my laptop anyhow.  They should use those eraser
things that IBM Thinkpads have.  Those work a lot better than touchpads
do --- more responsive, easier to control, less awkward, less carpal

Karl Hegbloom <hegbloom at>

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