pointer (touchpad) aceleration and threshold too low in 11.3.* builds

[Eduardo H. Silva]

2012/5/17 Paul Fox <pgf at laptop.org>:
> eduardo h. silva wrote:
>  > 2012/5/17 Paul Fox <pgf at laptop.org>:
>  > > eduardo h. silva wrote:
>  > >  > xset q tells that in 11.3.1, the pointer is configured with the values:
>  > >  >
>  > >  > acceleration 7/4 threshold: 1
>  > >  >
>  > >  > This takes 2, 3 and sometimes 4 swipes to move across the screen. It's
>  > >  > quite a difference with a typical touchpad on bigger laptops, and
>  > >  > although the experience can't be duplicated because we can't expect
>  > >  > kids to be already highly trained with a touchpad, I think it could be
>  > >  > improved.
>  > >  >
>  > >  > I think the balance is to have a larger threshold, so that slow
>  > >  > movements are allways acurate, and a higher acceleration, so that
>  > >  > movements across the screen are sufficiently fast (very important in
>  > >  > Sugar to access the frame for example). Managing to drop down the
>  > >  > amount of swipes needed to move across the screen (like 2 swipes)
>  > >  > would be excellent and more in par with the older pre 11.3.* behavior.
>  > >
>  > > so you think it was better, previously?
>  > >
>  > > i wonder what has changed.  those xset values were chosen specifically
>  > > to be appropriate for the original ALPS touchpad on XO-1.  it's
>  > > entirely possible, now that we're two laptops and at least as many
>  > > touchpads beyond that, those numbers are incorrect.
>  >
>  > I meant to compare between the setting of the builds back in 2008 and
>  > 2011 when I began using the XO after a hiatus of years.
>  >
>  > I found a discussion started about the change from "acceleration 7/4
>  > threshold: 1" to "acceleration 7/4 threshold: 0)
>  > (http://lists.laptop.org/pipermail/devel/2010-January/027245.html ). A
>  > few messages later, it's shown in xset man page:
>  >
>  > "If the `threshold' parameter is provided and 0, the
>  >     `acceleration' parameter will be used in the exponent of a
>  >     more natural and continous formula, giving precise control
>  >     for slow motion but big reach for fast motion, and a
>  >     progresive transition for motions in between.  Recommended
>  >     `acceleration' value in this case is 3/2 to 2, but not
>  >     limited to that range "
>  >
>  > Which is exactly what I was looking for. A bit later, Richard A. Smith tells:
>  >
>  > "2 of the apps that our deployments spend a lot of time in are scratch
>  > and etoys. Both of these are not completely sugarized apps  and thus
>  > some of the UI elements on the 200 dpi screen are quite small and hard
>  > to use with a fast accel." Though I don't know if he used higher
>  > acceleration values, or with threshold set to 0.
>  >
>  > So the thread ends with:
>  >
>  > "Find someone with kids and figure out whats the best settings for them."
>  >
>  > Next time I am with my nephews I'll be sure to do this, but I already
>  > find threshold 0 a lot better. Perhaps the problem Richard was having
>  > could be solved with a lower acceleration, like 3/2, but still with
>  > threshold 0.
>
> i'm sure you're right, and i think we had consensus around that
> several years ago.  it's my belief (after skimming old mail) that the
> very earliest X servers shipped on XO-1 a) did treat a threshold of 0
> as special, but b) did not do it correctly.  so using '1' at that time
> was deliberate.  but after a time we (i, certainly) agreed that we
> should be using 0.
>
> we also had a discussion about lowering the 7/4 -- at the time i thought
> 3/2 was too slow, and suggested 165/100, but i suspect that that's
> splitting hairs.  (i.e. 1.5 vs. 1.65).
>
> after verifying, we should at least fix the '0' threshold as a bug, in
> 12.1.0.
>
If it's to be fixed, can't it be changed for the upcoming 11.3.1 as well?

Eduardo