[gpm] flaky movement and buttons when using both stick and touchpad (ultranav)

Tavin Cole tavin.gguo@agilecomputing.com
Wed Nov 26 21:28:04 CET 2003

On Wed, 2003-11-26 at 17:20, Peter Berg Larsen wrote:
> *** debug [synaptics.c(1780)]: A tap? 0 < 14 < 16 && (18)^2 + (-17)^2 < 10000
> *** info [synaptics.c(1945)]: dx: -18.0  dy: -17.0  tdist^2: 613.0
> *** info [synaptics.c(1964)]: tossx: -3  tossy: -3
> You push the pad for a tap. (first line; both conditions are true). The
> finger motion on the pad, while doing the tap, is large/moved enough for
> it to also be consideret a toss. A toss stops when you touch the pad
> again; so you are tossing while pressing the stick and pushing the
> buttons. To stop this behaviour:

okay, i'm not really familiar with this tossing stuff, but i see that it
explains the behavior i have been seeing, to a degree (the motion bias
when using the stick or pressing the buttons).  however, the motion bias
never goes away, even after i touch the pad again, so that must be a

also there is the problem with the touchpad taps and buttons not working
until the pointer is moved a little with the touchpad.  that problem
recurs in the other cases i describe below.

as a side note, i think this tossing behavior, even bug-free, is
probably really confusing and unexpected to most people.  perhaps it
should be off by default, or at least min_toss_dist should be greater
than 2 mm, as i could not discern any sideways motion in my finger in
the taps i was doing.

> A) Disable toss, dooh. See the question below.
> B) Set a higher constant for min_toss_dist or min_toss_time.
> C) Apply following patch, which prevent a tap and a toss to be activated
>    at the same time.

> > > > i tried adding [tossing_enabled] FALSE.  with that, taps don't work at
> > > > all (i only had them set up to left click or left click + drag) and
> > > > neither do the touchpad buttons.  the random motion problems are gone,
> > > > but i suppose that's because taps do nothing now.
> So why does disabling tossing stop taps/buttons? (It should not influence
> it at all). Could you send some output where you press a button and  do a
> tap.

i investigated a little further:  with tossing_enabled FALSE, the
touchpad tapping and buttons work until the first time i use the stick
or stick buttons.  then the touchpad tapping and buttons never work
again.  i've attached debug output with tossing_enabled FALSE in which i
do a few touchpad taps and button clicks that work, then use the stick,
then do a few touchpad taps and button clicks that don't work.

if instead of setting tossing_enabled FALSE, i set max_toss_time 0,
everything is almost perfect.  the touchpad taps and buttons stop
working after i use the stick, but they work again if i move the pointer
a little with the touchpad.

thank you for your help.

Tavin Cole <tavin.gguo@agilecomputing.com>
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