Touchpad accel, spirals and xset

Paul Fox pgf at
Wed Jan 27 18:34:49 EST 2010

walter wrote:
 > (FWIW, I am still of the opinion that we may want to disable the
 > touchpad on the old hardware and re-enable the resistive pad, which
 > should be more immune to some of the problems we have been
 > experiencing.)

i've just pushed changes to the olpc-2.6.31 branch that let one
do exactly this, so it should appear in the next F11-on-XO1
release for people to play with.  it's lightly tested, but seems
robust enough for a first pass.

the only UI consists of:
    echo [1|0] > /sys/devices/platform/i8042/serio1/ptmode
to turn pen tablet mode on or off.  you can also add a a file to
the /etc/modprobe.d directory containing "options psmouse ptmode=1"
to force that mode at boot time.

note that this does _not_ give the laptop a true tablet device. 
what these changes basically let you do is select between two
different mouse-like touchpads:

    1) the current (capacitive) touchpad we all know and
	lov^H^H^Hhate, and

    2) a much wider (resistive) touchpad that behaves very
	similarly except that you have to press pretty hard with
	sylus (or maybe a fingernail) to get it to do anything. 
	it isn't jumpy, like the capacitive pad, but it does jump
	sometimes (on my laptop, at least) if you don't keep full
	pressure on continously.

please let me know what you think.  implementing a UI of some sort
to select the modes is someone else's department.


p.s. there are ifdefs in the driver for running the pen tablet as a true
tablet, with absolute positioning, but that mode isn't well thought
out, and isn't suitable for general use of the laptop.

 paul fox, pgf at

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