[PATCH] Input: wacom - Add POINTER and DIRECT device properties

Adds INPUT_PROP_POINTER or INPUT_PROP_DIRECT as necessary to the
hardware supported by the Wacom driver. The DIRECT property is
assigned to devices with an embedded screen (i.e. touchscreens
and display tablets). The POINTER property is assigned to those
without embedded screens.

Signed-off-by: Jason Gerecke <redacted>
---
 drivers/hid/hid-wacom.c                 |    2 ++
 drivers/input/tablet/wacom_wac.c        |   25 ++++++++++++++++++++++++-
 drivers/input/touchscreen/wacom_w8001.c |    2 ++
 3 files changed, 28 insertions(+), 1 deletions(-)

diff --git a/drivers/hid/hid-wacom.c b/drivers/hid/hid-wacom.c
index 0688832..5b9267d 100644
--- a/drivers/hid/hid-wacom.c
+++ b/drivers/hid/hid-wacom.c

@@ -383,6 +383,8 @@ move_on:
 	hidinput = list_entry(hdev->inputs.next, struct hid_input, list);
 	input = hidinput->input;
 
+	__set_bit(INPUT_PROP_POINTER, input->propbit);
+
 	/* Basics */
 	input->evbit[0] |= BIT(EV_KEY) | BIT(EV_ABS) | BIT(EV_REL);
 

diff --git a/drivers/input/tablet/wacom_wac.c b/drivers/input/tablet/wacom_wac.c
index 87b0e0d..a28d48c 100644
--- a/drivers/input/tablet/wacom_wac.c
+++ b/drivers/input/tablet/wacom_wac.c

@@ -1098,6 +1098,8 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 		__set_bit(BTN_TOOL_MOUSE, input_dev->keybit);
 		__set_bit(BTN_STYLUS, input_dev->keybit);
 		__set_bit(BTN_STYLUS2, input_dev->keybit);
+
+		__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
 		break;
 
 	case WACOM_21UX2:

@@ -1126,6 +1128,9 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 		}
 
 		input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
+
+		__set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
+
 		wacom_setup_cintiq(wacom_wac);
 		break;
 

@@ -1150,6 +1155,8 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 		/* fall through */
 
 	case INTUOS:
+		__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
+
 		wacom_setup_intuos(wacom_wac);
 		break;
 

@@ -1165,6 +1172,8 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 
 		input_set_abs_params(input_dev, ABS_Z, -900, 899, 0, 0);
 		wacom_setup_intuos(wacom_wac);
+
+		__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
 		break;
 
 	case TABLETPC2FG:

@@ -1183,14 +1192,24 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 	case TABLETPC:
 		__clear_bit(ABS_MISC, input_dev->absbit);
 
+		__set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
+
 		if (features->device_type != BTN_TOOL_PEN)
 			break;  /* no need to process stylus stuff */
 
 		/* fall through */
 
 	case PL:
-	case PTU:
 	case DTU:
+		__set_bit(BTN_TOOL_PEN, input_dev->keybit);
+		__set_bit(BTN_TOOL_RUBBER, input_dev->keybit);
+		__set_bit(BTN_STYLUS, input_dev->keybit);
+		__set_bit(BTN_STYLUS2, input_dev->keybit);
+
+		__set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
+		break;
+
+	case PTU:
 		__set_bit(BTN_STYLUS2, input_dev->keybit);
 		/* fall through */
 

@@ -1198,11 +1217,15 @@ void wacom_setup_input_capabilities(struct input_dev *input_dev,
 		__set_bit(BTN_TOOL_PEN, input_dev->keybit);
 		__set_bit(BTN_TOOL_RUBBER, input_dev->keybit);
 		__set_bit(BTN_STYLUS, input_dev->keybit);
+
+		__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
 		break;
 
 	case BAMBOO_PT:
 		__clear_bit(ABS_MISC, input_dev->absbit);
 
+		__set_bit(INPUT_PROP_POINTER, input_dev->propbit);
+
 		if (features->device_type == BTN_TOOL_DOUBLETAP) {
 			__set_bit(BTN_LEFT, input_dev->keybit);
 			__set_bit(BTN_FORWARD, input_dev->keybit);

diff --git a/drivers/input/touchscreen/wacom_w8001.c b/drivers/input/touchscreen/wacom_w8001.c
index c14412e..9941d39 100644
--- a/drivers/input/touchscreen/wacom_w8001.c
+++ b/drivers/input/touchscreen/wacom_w8001.c

@@ -383,6 +383,8 @@ static int w8001_setup(struct w8001 *w8001)
 	dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 	strlcat(w8001->name, "Wacom Serial", sizeof(w8001->name));
 
+	__set_bit(INPUT_PROP_DIRECT, dev->propbit);
+
 	/* penabled? */
 	error = w8001_command(w8001, W8001_CMD_QUERY, true);
 	if (!error) {

-- 
1.7.6

On Thu, Sep 1, 2011 at 9:00 AM, Jason Gerecke [off-list ref] wrote:

Adds INPUT_PROP_POINTER or INPUT_PROP_DIRECT as necessary to the
hardware supported by the Wacom driver. The DIRECT property is
assigned to devices with an embedded screen (i.e. touchscreens
and display tablets). The POINTER property is assigned to those
without embedded screens.

Signed-off-by: Jason Gerecke <redacted>

Reviewed-by: Ping Cheng <redacted>

Ping

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Hi Jason,

Adds INPUT_PROP_POINTER or INPUT_PROP_DIRECT as necessary to the
hardware supported by the Wacom driver. The DIRECT property is
assigned to devices with an embedded screen (i.e. touchscreens
and display tablets). The POINTER property is assigned to those
without embedded screens.

Signed-off-by: Jason Gerecke <redacted>
---

According to the discussion leading up to the properties interface
(https://lkml.org/lkml/2010/12/15/263), a tablet is a direct pointer
device, as opposed to a touchpad, which is an indirect pointer
device. The distinction determines the direction of two-finger scroll,
for instance. The question is then what behavior should be assigned to
a large tablet without an embedded screen. It should have POINTER set
for sure, but should it also have DIRECT set?

Thanks,
Henrik

Hi,

On Tue, Sep 13, 2011 at 10:09 AM, Henrik Rydberg [off-list ref] wrote:

The question is then what behavior should be assigned to
a large tablet without an embedded screen. It should have POINTER set
for sure, but should it also have DIRECT set?

Any large tablet without an embedded screen can be used in the 2 different ways:
1. The projection on top of it so it becomes a direct device.
(this case is also used when you project 3d 120hz on top of multitouch
devices: iMuts)

2. Simple indirect device, even if it's large:
http://10gui.com/video/

i

On Tue, Sep 13, 2011 at 3:09 AM, Henrik Rydberg [off-list ref] wrote:

Hi Jason,

quoted

Adds INPUT_PROP_POINTER or INPUT_PROP_DIRECT as necessary to the
hardware supported by the Wacom driver. The DIRECT property is
assigned to devices with an embedded screen (i.e. touchscreens
and display tablets). The POINTER property is assigned to those
without embedded screens.

Signed-off-by: Jason Gerecke <redacted>
---

According to the discussion leading up to the properties interface
(https://lkml.org/lkml/2010/12/15/263), a tablet is a direct pointer
device, as opposed to a touchpad, which is an indirect pointer
device. The distinction determines the direction of two-finger scroll,
for instance. The question is then what behavior should be assigned to
a large tablet without an embedded screen. It should have POINTER set
for sure, but should it also have DIRECT set?

Here are all the possible combinations based on my understanding of
their intended usage.

  * Touch interface without screen should have POINTER only to
indicate pointer needed and to treat absolute coordinates as relative
movement.  Relative movement is product's default behavior as
documented in its own manual and what I think should be advertised by
default.
 * Pen interface without screen should have both POINTER and DIRECT to
indicate pointer needed and to treat absolute coordinates as absolute
movement.
 * Touch interfaces with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
 * Pen interface with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
* A Pen+Touch touchscreen (only the wacom_w8001.c), should have DIRECT
only to indicate no pointer displayed and absolute coordinates as
absolute movement.

Assuming we all agree on those combination, then in the patch the
Graphire and Intuos tablets are missing a DIRECT, the touchscreens are
correct, and the Bamboo's need to add DIRECT for the PEN interface
only.

Chris

On Tue, Sep 13, 2011 at 7:13 AM, Chris Bagwell [off-list ref] wrote:

On Tue, Sep 13, 2011 at 3:09 AM, Henrik Rydberg [off-list ref] wrote:

quoted

Hi Jason,

quoted

Adds INPUT_PROP_POINTER or INPUT_PROP_DIRECT as necessary to the
hardware supported by the Wacom driver. The DIRECT property is
assigned to devices with an embedded screen (i.e. touchscreens
and display tablets). The POINTER property is assigned to those
without embedded screens.

Signed-off-by: Jason Gerecke <redacted>
---

According to the discussion leading up to the properties interface
(https://lkml.org/lkml/2010/12/15/263), a tablet is a direct pointer
device, as opposed to a touchpad, which is an indirect pointer
device. The distinction determines the direction of two-finger scroll,
for instance. The question is then what behavior should be assigned to
a large tablet without an embedded screen. It should have POINTER set
for sure, but should it also have DIRECT set?

We have discussed and debated the above before the patch was posted.

As Ikbel pointed out, a standalone tablet can be DIRECT or INDIRECT,
depending on how it is used. So, it is more a property that is decided
by the client than by the kernel driver.

Here are all the possible combinations based on my understanding of
their intended usage.

 * Touch interface without screen should have POINTER only to
indicate pointer needed and to treat absolute coordinates as relative
movement.  Relative movement is product's default behavior as
documented in its own manual and what I think should be advertised by
default.
 * Pen interface without screen should have both POINTER and DIRECT to
indicate pointer needed and to treat absolute coordinates as absolute
movement.

Reporting it as DIRECT indicates it can only be used as DIRECT. We
don't want client to make that assumption. User-land clients can
distinguish a touch POINTER from a pen POINTER by the tool types.

 * Touch interfaces with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
 * Pen interface with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
* A Pen+Touch touchscreen (only the wacom_w8001.c), should have DIRECT
only to indicate no pointer displayed and absolute coordinates as
absolute movement.

Assuming we all agree on those combination, then in the patch the
Graphire and Intuos tablets are missing a DIRECT, the touchscreens are
correct, and the Bamboo's need to add DIRECT for the PEN interface
only.

I agree with all the other assumptions except this one.

Ping
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On Tue, Sep 13, 2011 at 12:36 PM, Ping Cheng [off-list ref] wrote:

On Tue, Sep 13, 2011 at 7:13 AM, Chris Bagwell [off-list ref] wrote:

quoted

On Tue, Sep 13, 2011 at 3:09 AM, Henrik Rydberg [off-list ref] wrote:

quoted

Hi Jason,

quoted

Adds INPUT_PROP_POINTER or INPUT_PROP_DIRECT as necessary to the
hardware supported by the Wacom driver. The DIRECT property is
assigned to devices with an embedded screen (i.e. touchscreens
and display tablets). The POINTER property is assigned to those
without embedded screens.

Signed-off-by: Jason Gerecke <redacted>
---

According to the discussion leading up to the properties interface
(https://lkml.org/lkml/2010/12/15/263), a tablet is a direct pointer
device, as opposed to a touchpad, which is an indirect pointer
device. The distinction determines the direction of two-finger scroll,
for instance. The question is then what behavior should be assigned to
a large tablet without an embedded screen. It should have POINTER set
for sure, but should it also have DIRECT set?

We have discussed and debated the above before the patch was posted.

As Ikbel pointed out, a standalone tablet can be DIRECT or INDIRECT,
depending on how it is used. So, it is more a property that is decided
by the client than by the kernel driver.

I've a couple questions that would help me decide how things should be declared.

Can DIRECT be translated to mean treat coordinates as absolute
coordinates mapped to screen?  Or is it meant to be reserved only for
the more specific touchscreen-like application were the touch is laid
directly on top of the object being manipulated (or picture is
overlaid the touch for projector case)?

If some company shipped a touchpad+projector, would that ideally
declare DIRECT and not declare POINTER since user is directly touching
objects and the display of a pointer would serve no purpose?

What I'm getting at with the second question is if user pairs up a
touch tablet/touchpad with a projector then declaring even POINTER may
be just as wrong as not declaring DIRECT.

I don't think we can every get custom HW applications declared
correctly, so do we punish all cases and not declare anything?

quoted

Here are all the possible combinations based on my understanding of
their intended usage.

 * Touch interface without screen should have POINTER only to
indicate pointer needed and to treat absolute coordinates as relative
movement.  Relative movement is product's default behavior as
documented in its own manual and what I think should be advertised by
default.
 * Pen interface without screen should have both POINTER and DIRECT to
indicate pointer needed and to treat absolute coordinates as absolute
movement.

Reporting it as DIRECT indicates it can only be used as DIRECT. We
don't want client to make that assumption. User-land clients can
distinguish a touch POINTER from a pen POINTER by the tool types.

I see your logic now and patch does follow that logic.

I can actually buy into that although it seems to make the need for
both POINTER and DIRECT redundant. Touchscreen = DIRECT while Tablet
(pen, touch, or both) = POINTER.  No overlap.

If we do allow DIRECT on tablets then I do see now it becomes a
relaxed DIRECT since application will most likely still offer
switching pens to relative mode.

Chris

quoted

 * Touch interfaces with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
 * Pen interface with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
* A Pen+Touch touchscreen (only the wacom_w8001.c), should have DIRECT
only to indicate no pointer displayed and absolute coordinates as
absolute movement.

Assuming we all agree on those combination, then in the patch the
Graphire and Intuos tablets are missing a DIRECT, the touchscreens are
correct, and the Bamboo's need to add DIRECT for the PEN interface
only.

I agree with all the other assumptions except this one.

Ping

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I disagree with this assignment somewhat because it creates ambiguities.

On Tue, Sep 13, 2011 at 7:13 AM, Chris Bagwell [off-list ref] wrote:

 * Touch interface without screen should have POINTER only to
indicate pointer needed and to treat absolute coordinates as relative
movement.  Relative movement is product's default behavior as
documented in its own manual and what I think should be advertised by
default.

Yes.

 * Pen interface without screen should have both POINTER and DIRECT to
indicate pointer needed and to treat absolute coordinates as absolute
movement.

No.  DIRECT should not be set because the Pen is not directly touching
the objects on a screen.  The motions must still be translated through
some indirect means (a mapping function) onto the plane of the screen.

Therefore should only specify POINTER.

 * Touch interfaces with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
 * Pen interface with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
* A Pen+Touch touchscreen (only the wacom_w8001.c), should have DIRECT
only to indicate no pointer displayed and absolute coordinates as
absolute movement.

Yes, but not for this reason.  Touch interfaces with screen should
have DIRECT to indicate that touches are directly upon objects on the
screen.

It happens that the absolute coordinates of a tablet are usually
mapped 1-1 with the screen, but that's not what is meant by a direct
input device.  It's the usage that matters, not the mapping function
itself.

Note that a tablet's mapping function need not be precisely 1-1.  It
could be constrained to part of a window on the display, or it could
be rotated or skewed with respect to the display.  This is a
fundamental difference between direct and indirect input devices.  The
mapping function for a direct input devices must be a natural mapping
based on what is actually seen and directly touches.  The mapping
function for an indirect input device can be almost anything because a
pointer is being used to provide visual feedback so it is not
constrained by the physical position of objects on screen.

Assuming we all agree on those combination, then in the patch the
Graphire and Intuos tablets are missing a DIRECT, the touchscreens are
correct, and the Bamboo's need to add DIRECT for the PEN interface
only.

I disagree.

A touchscreen is DIRECT.
A tablet or trackpad is INDIRECT (and POINTER).

Further absolute/relative distinctions need to be made by tool.
Finger / mouse on tablet uses relative motion.  Pen uses absolute
motion.  Essentially the tool types qualify the mapping function used
by indirect devices.

This isn't a concern for direct devices because there's really only
one sensible mapping function to use... touch the thing under the
finger.  :)

Jeff.
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quoted

 * Pen interface without screen should have both POINTER and DIRECT to
indicate pointer needed and to treat absolute coordinates as absolute
movement.

No.  DIRECT should not be set because the Pen is not directly touching
the objects on a screen.  The motions must still be translated through
some indirect means (a mapping function) onto the plane of the screen.

Therefore should only specify POINTER.

This is wrong given the intended semantics. Regardless of if DIRECT
means "absolute coordinates" or "one-to-one with screen", the result
is the same.

quoted

 * Touch interfaces with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
 * Pen interface with screen should have DIRECT only to indicate no
pointer displayed and absolute coordinates as absolute movement.
* A Pen+Touch touchscreen (only the wacom_w8001.c), should have DIRECT
only to indicate no pointer displayed and absolute coordinates as
absolute movement.

Yes, but not for this reason.  Touch interfaces with screen should
have DIRECT to indicate that touches are directly upon objects on the
screen.

A one-to-one correspondence should suffice.

It happens that the absolute coordinates of a tablet are usually
mapped 1-1 with the screen, but that's not what is meant by a direct
input device.  It's the usage that matters, not the mapping function
itself.

Precisely - it is the usage that matters here.

Note that a tablet's mapping function need not be precisely 1-1.  It
could be constrained to part of a window on the display, or it could
be rotated or skewed with respect to the display.  This is a
fundamental difference between direct and indirect input devices.  The
mapping function for a direct input devices must be a natural mapping
based on what is actually seen and directly touches.  The mapping
function for an indirect input device can be almost anything because a
pointer is being used to provide visual feedback so it is not
constrained by the physical position of objects on screen.

The fundamental difference between a touchscreen and the mapping you
describe here is POINTER, not DIRECT. There is no reason why a device
physically separated from the screen, and guided by one or several
markers, cannot behave the same way as a touchscreen.

quoted

Assuming we all agree on those combination, then in the patch the
Graphire and Intuos tablets are missing a DIRECT, the touchscreens are
correct, and the Bamboo's need to add DIRECT for the PEN interface
only.

I disagree.

A touchscreen is DIRECT.
A tablet or trackpad is INDIRECT (and POINTER).

Based on your assmumptions on the semantics, you are of course
right. Given the actual intended semantics, this is wrong. It is as
far as we get.

Further absolute/relative distinctions need to be made by tool.
Finger / mouse on tablet uses relative motion.  Pen uses absolute
motion.  Essentially the tool types qualify the mapping function used
by indirect devices.

Aggred, the pen tablets we see today behave this way, and we do not
break anything by skipping the DIRECT property here.

Thanks,
Henrik
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