[PATCH evdev] Added Sensitivity option

Hans Nieser hnsr at xs4all.nl
Sat Jan 2 07:25:38 PST 2010

On Fri, 2010-01-01 at 20:19 +0100, Simon Thum wrote:
> epsy wrote:
> > On 01/01/2010 12:30, Simon Thum wrote:
> >> Another consideration, maybe 'constant deceleration' simply isn't
> >> descriptive enough? I'm not a native speaker, so I'm pretty much lost on
> >> this one.
> >>   
> > Hmm, you're spot on. I googled since I got this high-dpi mouse and found
> > nothing but a patch against an older evdev and mouse-specific options.
> > This setting went rather unnoticed as I was looking for a linear
> > physical movement/pointer movement curve, and that in my book "pointer
> > acceleration" is the opposite of this. Add to this it doesn't seem to be
> > documented(or what manpage refers to it?) and I totally miss it :) Well
> > thanks for the info and I guess that's a lesson taken.
> Yeah, it's under-documented. In a few days, the xset and xinput man
> pages should be more telling.
> If google wasn't a battleground, you might have stumbled on this:
> http://www.x.org/wiki/Development/Documentation/PointerAcceleration#head-f7ec05618a8668279f413205aea5065996548144
> Some considerations:
> ATM constant deceleration is intertwined with acceleration code, but it
> really is linear. Or constant, as seen from the factor over velocity
> curve. Anyway, this term seems overcomplicated, and I'm even unsure it's
> technically correct. Also, from a user's pov it really doesn't have
> anything to do with acceleration. So I think a rename is appropriate,
> given DE's haven't yet adapted to it anyway.
> I came across "Sensitivity", "Scaling", "Downscaling" and "Decelearation".
> Also, the "Device Accel" in "Device Accel Constant Deceleration" is
> somewhat questionable. It reflects implementation, rather than useage.
> AFAIR "Device" is intended as a hint that it affects a slave (not
> master) device, but the "Accel" is purely implementation.
> To sum up, I'm fine with e.g. "Device Downscaling" or the like.
> What do you think?*

I too stumbled into this issue with my high-dpi mouse, fortunately I did
manage to find the constant deceleration option through the Xorg wiki
article you linked.

To me 'sensitivity' ('device sensitivity'?) would make most sense but
it's already been used in other places and I guess that might make it
confusing. (For example Gnome's mouse settings dialog already has a
'sensitivity' setting and it doesn't do anything like constant

Personally I find 'device downscaling' to sound reasonable, or at least
a bit more illuminating than the current name

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