On Thu, Aug 18, 2011 at 12:32 AM, Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> wrote:
>
> On Wed, Aug 17, 2011 at 10:05:48PM +0800, Daniel Kurtz wrote:
> > On Mon, Aug 15, 2011 at 3:17 PM, Daniel Kurtz <djkurtz@xxxxxxxxxxxx> wrote:
> > >
> > > Hi Henrik,
> > >
> > > Thanks for the great feedback.
> > >
> > > On Sat, Aug 13, 2011 at 5:09 AM, Henrik Rydberg <rydberg@xxxxxxxxxxx> wrote:
> > > > Hi Daniel,
> > > >
> > > > looks good, some details below.
> > > >
> > > > The ABS_MT_TOUCH_MAJOR is supposed to have zero intercept, to remain
> > > > compatible with user space handling of type A devices. Also, the scale
> > > > should match the screen/pad size, such that the actual size of the
> > > > touch area can be deduced. In addition, based on the current sensor
> > > > technologies, ABS_MT_PRESSURE and ABS_MT_TOUCH_MAJOR are normally
> > > > mutually exclusive.
> > > >
> > > > All in all, I would prefer to only report width via (the single-finger
> > > > axis) ABS_TOOL_WIDTH, and only for compatibility reasons.
> > > >
> > > > +
> > > > +static void synaptics_report_slot_agm(struct input_dev *dev, int slot,
> > > > + const struct synaptics_hw_state *agm)
> > > > +{
> > > > + input_mt_slot(dev, slot);
> > > > + input_mt_report_slot_state(dev, MT_TOOL_FINGER, true);
> > > > + input_report_abs(dev, ABS_MT_POSITION_X, agm->x);
> > > > + input_report_abs(dev, ABS_MT_POSITION_Y, invert_y(agm->y));
> > > > + input_report_abs(dev, ABS_MT_PRESSURE, agm->z);
> > > > +}
> > >
> > > With ABS_MT_TOUCH_MAJOR dropped, sgm and agm seems to coincide...
> > > ....
> > > >
> > > > Looks good otherwise.
> > > >
> > > > Thanks,
> > > > Henrik
> > > >
> > >
> > > Ahh.... ok, this makes sense. I missed this detail previously.
> > > Basically:
> > > * Only report synaptics "w" as ABS_TOOL_WIDTH (for backwards compatibility)
> > > * Report synaptics "z" as ABS_MT_TOUCH_MAJOR (assuming it is really
> > > 'width of finger in surface units'), and ABS_PRESSURE (for backwards
> > > compatibility).
> > > * Don't use ABS_MT_PRESSURE.
> > > * This will simplify agm/sgm reporting by making them both reoprt
> > > the same axes.
> >
> > Hi Henrik,
> >
> > I think I was wrong in my previous comment.
> >
> > I agree we should drop reporting synaptics 'w' (4-15, arbitrary units)
> > in ABS_MT_TOUCH_MAJOR.
> > Instead, to support legacy, report 'w' in ABS_TOOL_WIDTH, and do not
> > report ABS_MT_TOUCH_MAJOR at all.
> >
> > However, I believe we should still report synaptics 'z' (0-255, in
> > arbitrary units) as ABS_MT_PRESSURE.
> > This will, in turn, be used by input_mt_report_pointer_emulation() to
> > determine the correct ABS_PRESSURE to report for legacy userspace
> > uses.
>
> Alternatively, you can use input_mt_set_value() to save Z value to be
> used by input_mt_report_pointer_emulation() later, but not report it as
> part of MT packet.
>
> --
> Dmitry
But I want userspace to get per-contact pressure, since it is used to
determine whether a given contact is a palm or finger, etc. The
trackpad does not report a useful per-contact "width" that can be used
to generate "TOUCH_MAJOR".
Does it therefore sound reasonable to report ABS_MT_PRESSURE?
-Dan
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