Re: [PATCH] Synaptics TouchPad driver for 2.5.70

[Vojtech Pavlik]

On Wed, Jun 11, 2003 at 08:16:13PM +0200, Peter Osterlund wrote:

> Actually, the runtime configuration may not be needed at all if we do
> the ABS -> REL conversion in user space, because all parameters
> control different aspects of this conversion.

That'd be very nice.

> > > The patch is available here:
> > > 
> > >         http://w1.894.telia.com/~u89404340/patches/synaptics_driver.patch
> > > 
> > > Comments?
> > 
> > IMO it should use ABS_ events and the relativization should be done in
> > the XFree86 driver. Other than that, it looks quite OK.
> 
> OK, the hardware state consists of 4 "axes" and 4 buttons, as defined
> in the synaptics_hw_state struct:
> 
>         struct synaptics_hw_state {
>         	int x;
>         	int y;
>         	int z;
>         	int w;
>         	int left;
>         	int right;
>         	int up;
>         	int down;
>         };
> 
> x and y are the finger position, z is the finger pressure and w
> contains information about multifinger taps and finger width (for palm
> detection.) Left, right, up and down contain the state of the
> corresponding physical buttons.
> 
> Is this mapping reasonable?
> 
>         x     -> ABS_X
>         y     -> ABS_Y
>         z     -> ABS_PRESSURE
>         w     -> ABS_MISC
>         left  -> BTN_LEFT
>         right -> BTN_RIGHT
>         up    -> BTN_FORWARD
>         down  -> BTN_BACK

Yes, this is fine.

> The w value is somewhat special and not really a real axis. According
> to the Synaptics TouchPad Interfacing Guide
> (http://www.synaptics.com/decaf/utilities/ACF126.pdf), W is defined as
> follows:
> 
> Value		Needed capability	Interpretation
> W = 0		capMultiFinger		Two fingers on the pad.
> W = 1		capMultiFinger		Three or more fingers on the pad.
> W = 2		capPen			Pen (instead of finger) on the pad.
> W = 3		Reserved.
> W = 4-7		capPalmDetect		Finger of normal width.
> W = 8-14	capPalmDetect		Very wide finger or palm.
> W = 15		capPalmDetect		Maximum reportable width; extremely
> 					wide contact.
> 
> Is there a better way than using ABS_MISC to pass the W information to
> user space?

I think ABS_MISC is perfectly okay for this.

-- 
Vojtech Pavlik
SuSE Labs, SuSE CR