Re: [PATCH 2/2] input: mousedev: Emulate right and middle buttonsfor single-button touchpads

From: Dmitry Torokhov
Date: Wed Sep 10 2008 - 11:32:31 EST


On Wed, Sep 10, 2008 at 04:51:52PM +0200, Henrik Rydberg wrote:
> Greetings Dmitry,
>
> > On Fri, Sep 05, 2008 at 03:19:56AM +0200, Henrik Rydberg wrote:
> >> On most linux-based systems, the right and middle buttons are used
> >> extensively. On computers lacking either of those buttons, such as
> >> the Apple Macbooks, emulation is needed. This patch adds emulation
> >> of the missing buttons via two-fingers-and-click and three-fingers-
> >> and-click operations, which has recently become standard, both in
> >> MacOS and in the Xorg synaptics driver.
> >>
> >
> > The standard way of emulating right and middle button presses for
> > "button-deficient" devices is to use Macintosh emulation
> > (MAC_EMUMOUSEBTN) that works not only for touchpads but for regular mice
> > as well.
>
> I have a hard time believing that in five years from now, people will
> still consider pressing a key on the keyboard the standard way to
> emulate a right click.

Well, what other options do you have if your device has only one
button and nothing else (i.e. it's a mouse, not a touchpad)? Anyway, I
hope in 5 years distros will switch to pure evdev-based interfaces and
won't use mousedev at all.

> Nevertheless, I can see the point in moving
> away from user-land decisions in the kernel. I will not pursue this one
> further, although it is a rather neat piece of functionality.
>
> > Overall I don't think we should enhance mousedev for scenarios where
> > proper solution is to install Synaptics X driver. This also goes for
> > your other patch improving tapping in mousedev.
>
> Regarding the tapping patch; it is addressing the correctness of
> already implemented functionality. I can see nothing wrong with that.
>

My position that since the isssue can be "fixed" by simply installing
the proper X driver I'd rather not include it. Mousedev purpose is to
provide good enough emulation in absence of a native driver and that's
it. Also, the default value would not work well on high-resiolution
devices (like Synaptics) and would require user fiddling with kernel
parameters - not worth it in my opinion.

--
Dmitry
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