Re: [PATCH] Input: Add MT_TOOL_PALM

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Fri, Mar 20, 2015 at 08:41:55AM +1000, Peter Hutterer wrote:
> On Wed, Mar 18, 2015 at 03:26:35PM -0700, Charlie Mooney wrote:
> > Currently there are only two "tools" that can be specified by a
> > multi-touch driver: MT_TOOL_FINGER and MT_TOOL_PEN.  In working with
> > Elan (The touch vendor) and discussing their next-gen devices it
> > seems that it will be useful to have more tools so that their devices
> > can give the upper layers of the stack hints as to what is touching
> > the sensor.
> > 
> > In particular they have new experimental firmware that can better
> > differentiate between palms vs fingertips and would like to plumb a
> > patch so that we can use their hints in higher-level gesture soft-
> > ware.  The firmware on the device can reasonably do a better job of
> > palm detection because it has access to all of the raw sensor readings
> > as opposed to just the width/pressure/etc that are exposed by the
> > driver.  As such, the firmware can characterize what a palm looks like
> > in much finer-grained detail and this change would allow such a
> > device to share its findings with the kernel.
> > 
> > Signed-off-by: Charlie Mooney <charliemooney@chromium.org>
> 
> Acked-by: Peter Hutterer <peter.hutterer@who-t.net>

Applied, thank you.

> 
> Cheers,
>    Peter
> 
> > ---
> >  Documentation/input/multi-touch-protocol.txt | 9 ++++++---
> >  include/uapi/linux/input.h                   | 3 ++-
> >  2 files changed, 8 insertions(+), 4 deletions(-)
> > 
> > diff --git a/Documentation/input/multi-touch-protocol.txt b/Documentation/input/multi-touch-protocol.txt
> > index 7b4f59c..b85d000 100644
> > --- a/Documentation/input/multi-touch-protocol.txt
> > +++ b/Documentation/input/multi-touch-protocol.txt
> > @@ -312,9 +312,12 @@ ABS_MT_TOOL_TYPE
> >  
> >  The type of approaching tool. A lot of kernel drivers cannot distinguish
> >  between different tool types, such as a finger or a pen. In such cases, the
> > -event should be omitted. The protocol currently supports MT_TOOL_FINGER and
> > -MT_TOOL_PEN [2]. For type B devices, this event is handled by input core;
> > -drivers should instead use input_mt_report_slot_state().
> > +event should be omitted. The protocol currently supports MT_TOOL_FINGER,
> > +MT_TOOL_PEN, and MT_TOOL_PALM [2]. For type B devices, this event is handled
> > +by input core; drivers should instead use input_mt_report_slot_state().
> > +A contact's ABS_MT_TOOL_TYPE may change over time while still touching the
> > +device, because the firmware may not be able to determine which tool is being
> > +used when it first appears.
> >  
> >  ABS_MT_BLOB_ID
> >  
> > diff --git a/include/uapi/linux/input.h b/include/uapi/linux/input.h
> > index b0a8130..2f62ab2 100644
> > --- a/include/uapi/linux/input.h
> > +++ b/include/uapi/linux/input.h
> > @@ -973,7 +973,8 @@ struct input_keymap_entry {
> >   */
> >  #define MT_TOOL_FINGER		0
> >  #define MT_TOOL_PEN		1
> > -#define MT_TOOL_MAX		1
> > +#define MT_TOOL_PALM		2
> > +#define MT_TOOL_MAX		2
> >  
> >  /*
> >   * Values describing the status of a force-feedback effect
> > -- 
> > 2.1.2
> > 

-- 
Dmitry