[RFC v2] input: Introduce device information ioctl

[RFC v2] input: Introduce device information ioctl

[Henrik Rydberg]

Today, userspace sets up an input device based on the data it emits.
This is not always enough; a tablet and a touchscreen may emit exactly
the same data, for instance, but the former should be set up with a
pointer whereas the latter does not need to. Recently, a new type of
touchpad has emerged where the buttons are under the pad, which
changes handling logic without changing the emitted data. This patch
introduces a new ioctl, EVIOCGPROP, which enables user access to a set
of device properties useful during setup. The properties are given as
a bitmap in the same fashion as the event types.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
---
Hi all,

Here is version two of the device information proposal. In addition to
implementing the feedback, this version only defines a single combined
type/capabilities field. Since we want to support a device being of
multiple types, it suggests that we are really after the properties
that make up a type, rather than the types themselves. And since
quirks are also properties, we end up with a single bitmap of
properties instead.

As an example of how this would work for the
touchpad/tablet/touchscreen triplet, there are two properties defined,
INPUT_PROP_POINTER and INPUT_PROP_DIRECT. A touchpad is an indirect
pointer device, a tablet is a direct pointer device, and the
touchscreen is simply a direct device.

What do you think?

Thanks,
Henrik

PS. As before, the patch compiles, but is not further tested.

 drivers/input/evdev.c |    4 ++++
 drivers/input/input.c |    2 ++
 include/linux/input.h |   16 ++++++++++++++++
 3 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index e3f7fc6..0cd97e8 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -677,6 +677,10 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 #define EVIOC_MASK_SIZE(nr)	((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
 	switch (EVIOC_MASK_SIZE(cmd)) {
 
+	case EVIOCGPROP(0):
+		return bits_to_user(dev->propbit, INPUT_PROP_MAX,
+				    size, p, compat_mode);
+
 	case EVIOCGKEY(0):
 		return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
 
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 37708d1..ac751ce 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -1409,6 +1409,7 @@ INPUT_DEV_CAP_ATTR(LED, led);
 INPUT_DEV_CAP_ATTR(SND, snd);
 INPUT_DEV_CAP_ATTR(FF, ff);
 INPUT_DEV_CAP_ATTR(SW, sw);
+INPUT_DEV_CAP_ATTR(INPUT_PROP, prop);
 
 static struct attribute *input_dev_caps_attrs[] = {
 	&dev_attr_ev.attr,
@@ -1420,6 +1421,7 @@ static struct attribute *input_dev_caps_attrs[] = {
 	&dev_attr_snd.attr,
 	&dev_attr_ff.attr,
 	&dev_attr_sw.attr,
+	&dev_attr_prop.attr,
 	NULL
 };
 
diff --git a/include/linux/input.h b/include/linux/input.h
index b3a1e02..53d6364 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -91,6 +91,7 @@ struct input_keymap_entry {
 #define EVIOCGNAME(len)		_IOC(_IOC_READ, 'E', 0x06, len)		/* get device name */
 #define EVIOCGPHYS(len)		_IOC(_IOC_READ, 'E', 0x07, len)		/* get physical location */
 #define EVIOCGUNIQ(len)		_IOC(_IOC_READ, 'E', 0x08, len)		/* get unique identifier */
+#define EVIOCGPROP(len)		_IOC(_IOC_READ, 'E', 0x09, len)		/* get device properties */
 
 #define EVIOCGKEY(len)		_IOC(_IOC_READ, 'E', 0x18, len)		/* get global key state */
 #define EVIOCGLED(len)		_IOC(_IOC_READ, 'E', 0x19, len)		/* get all LEDs */
@@ -108,6 +109,18 @@ struct input_keymap_entry {
 #define EVIOCGRAB		_IOW('E', 0x90, int)			/* Grab/Release device */
 
 /*
+ * Device properties and quirks
+ */
+
+#define INPUT_PROP_POINTER		0x00	/* needs a pointer */
+#define INPUT_PROP_DIRECT		0x01	/* direct object manipulation */
+#define INPUT_PROP_BUTTONPAD		0x02	/* has button(s) under pad */
+#define INPUT_PROP_SEMI_MT		0x03	/* touch rectangle only */
+
+#define INPUT_PROP_MAX			0x1f
+#define INPUT_PROP_CNT			(INPUT_PROP_MAX + 1)
+
+/*
  * Event types
  */
 
@@ -1090,6 +1103,7 @@ struct ff_effect {
  * @phys: physical path to the device in the system hierarchy
  * @uniq: unique identification code for the device (if device has it)
  * @id: id of the device (struct input_id)
+ * @propbit: bitmap of device properties and quirks
  * @evbit: bitmap of types of events supported by the device (EV_KEY,
  *	EV_REL, etc.)
  * @keybit: bitmap of keys/buttons this device has
@@ -1173,6 +1187,8 @@ struct input_dev {
 	const char *uniq;
 	struct input_id id;
 
+	unsigned long propbit[BITS_TO_LONGS(INPUT_PROP_CNT)];
+
 	unsigned long evbit[BITS_TO_LONGS(EV_CNT)];
 	unsigned long keybit[BITS_TO_LONGS(KEY_CNT)];
 	unsigned long relbit[BITS_TO_LONGS(REL_CNT)];
-- 
1.7.2.3

Re: [RFC v2] input: Introduce device information ioctl

[Chase Douglas]

On 12/15/2010 02:20 PM, Henrik Rydberg wrote:
> Today, userspace sets up an input device based on the data it emits.
> This is not always enough; a tablet and a touchscreen may emit exactly
> the same data, for instance, but the former should be set up with a
> pointer whereas the latter does not need to. Recently, a new type of
> touchpad has emerged where the buttons are under the pad, which
> changes handling logic without changing the emitted data. This patch
> introduces a new ioctl, EVIOCGPROP, which enables user access to a set
> of device properties useful during setup. The properties are given as
> a bitmap in the same fashion as the event types.
> 
> Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
> ---
> Hi all,
> 
> Here is version two of the device information proposal. In addition to
> implementing the feedback, this version only defines a single combined
> type/capabilities field. Since we want to support a device being of
> multiple types, it suggests that we are really after the properties
> that make up a type, rather than the types themselves. And since
> quirks are also properties, we end up with a single bitmap of
> properties instead.
> 
> As an example of how this would work for the
> touchpad/tablet/touchscreen triplet, there are two properties defined,
> INPUT_PROP_POINTER and INPUT_PROP_DIRECT. A touchpad is an indirect
> pointer device, a tablet is a direct pointer device, and the
> touchscreen is simply a direct device.
> 
> What do you think?

I must have missed the first version of this patch, but I give two
thumbs way up :). The detection code for touchpad/tablet/touchscreen in
xf86-input-evdev is large and unwieldy, and seemingly simple changes to
an input driver can cause incorrect interpretation. Having this
available should help quite a bit!

Acked-by: Chase Douglas <chase.douglas@canonical.com>

Re: [RFC v2] input: Introduce device information ioctl

[Dmitry Torokhov]

On Wednesday, December 15, 2010 01:16:28 pm Chase Douglas wrote:
> On 12/15/2010 02:20 PM, Henrik Rydberg wrote:
> > Today, userspace sets up an input device based on the data it emits.
> > This is not always enough; a tablet and a touchscreen may emit exactly
> > the same data, for instance, but the former should be set up with a
> > pointer whereas the latter does not need to. Recently, a new type of
> > touchpad has emerged where the buttons are under the pad, which
> > changes handling logic without changing the emitted data. This patch
> > introduces a new ioctl, EVIOCGPROP, which enables user access to a set
> > of device properties useful during setup. The properties are given as
> > a bitmap in the same fashion as the event types.
> > 
> > Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
> > ---
> > Hi all,
> > 
> > Here is version two of the device information proposal. In addition to
> > implementing the feedback, this version only defines a single combined
> > type/capabilities field. Since we want to support a device being of
> > multiple types, it suggests that we are really after the properties
> > that make up a type, rather than the types themselves. And since
> > quirks are also properties, we end up with a single bitmap of
> > properties instead.
> > 
> > As an example of how this would work for the
> > touchpad/tablet/touchscreen triplet, there are two properties defined,
> > INPUT_PROP_POINTER and INPUT_PROP_DIRECT. A touchpad is an indirect
> > pointer device, a tablet is a direct pointer device, and the
> > touchscreen is simply a direct device.
> > 
> > What do you think?
> 
> I must have missed the first version of this patch, but I give two
> thumbs way up :). The detection code for touchpad/tablet/touchscreen in
> xf86-input-evdev is large and unwieldy, and seemingly simple changes to
> an input driver can cause incorrect interpretation. Having this
> available should help quite a bit!
> 
> Acked-by: Chase Douglas <chase.douglas@canonical.com>

As long as we document that !pointer && !direct means "unknown" or
"unspecified" so as to avoid having to update all devices at once that
should be OK.

We also need to wire up uinput.

Thanks.

-- 
Dmitry

Re: [RFC v2] input: Introduce device information ioctl

[Peter Hutterer]

On Wed, Dec 15, 2010 at 08:20:07PM +0100, Henrik Rydberg wrote:
> Today, userspace sets up an input device based on the data it emits.
> This is not always enough; a tablet and a touchscreen may emit exactly
> the same data, for instance, but the former should be set up with a
> pointer whereas the latter does not need to. Recently, a new type of
> touchpad has emerged where the buttons are under the pad, which
> changes handling logic without changing the emitted data. This patch
> introduces a new ioctl, EVIOCGPROP, which enables user access to a set
> of device properties useful during setup. The properties are given as
> a bitmap in the same fashion as the event types.
> 
> Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
> ---
> Hi all,
> 
> Here is version two of the device information proposal. In addition to
> implementing the feedback, this version only defines a single combined
> type/capabilities field. Since we want to support a device being of
> multiple types, it suggests that we are really after the properties
> that make up a type, rather than the types themselves. And since
> quirks are also properties, we end up with a single bitmap of
> properties instead.
> 
> As an example of how this would work for the
> touchpad/tablet/touchscreen triplet, there are two properties defined,
> INPUT_PROP_POINTER and INPUT_PROP_DIRECT. A touchpad is an indirect
> pointer device, a tablet is a direct pointer device, and the
> touchscreen is simply a direct device.
> 
> What do you think?
> 
> Thanks,
> Henrik
> 
> PS. As before, the patch compiles, but is not further tested.
> 
>  drivers/input/evdev.c |    4 ++++
>  drivers/input/input.c |    2 ++
>  include/linux/input.h |   16 ++++++++++++++++
>  3 files changed, 22 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> index e3f7fc6..0cd97e8 100644
> --- a/drivers/input/evdev.c
> +++ b/drivers/input/evdev.c
> @@ -677,6 +677,10 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
>  #define EVIOC_MASK_SIZE(nr)	((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
>  	switch (EVIOC_MASK_SIZE(cmd)) {
>  
> +	case EVIOCGPROP(0):
> +		return bits_to_user(dev->propbit, INPUT_PROP_MAX,
> +				    size, p, compat_mode);
> +
>  	case EVIOCGKEY(0):
>  		return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
>  
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index 37708d1..ac751ce 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -1409,6 +1409,7 @@ INPUT_DEV_CAP_ATTR(LED, led);
>  INPUT_DEV_CAP_ATTR(SND, snd);
>  INPUT_DEV_CAP_ATTR(FF, ff);
>  INPUT_DEV_CAP_ATTR(SW, sw);
> +INPUT_DEV_CAP_ATTR(INPUT_PROP, prop);
>  
>  static struct attribute *input_dev_caps_attrs[] = {
>  	&dev_attr_ev.attr,
> @@ -1420,6 +1421,7 @@ static struct attribute *input_dev_caps_attrs[] = {
>  	&dev_attr_snd.attr,
>  	&dev_attr_ff.attr,
>  	&dev_attr_sw.attr,
> +	&dev_attr_prop.attr,
>  	NULL
>  };
>  
> diff --git a/include/linux/input.h b/include/linux/input.h
> index b3a1e02..53d6364 100644
> --- a/include/linux/input.h
> +++ b/include/linux/input.h
> @@ -91,6 +91,7 @@ struct input_keymap_entry {
>  #define EVIOCGNAME(len)		_IOC(_IOC_READ, 'E', 0x06, len)		/* get device name */
>  #define EVIOCGPHYS(len)		_IOC(_IOC_READ, 'E', 0x07, len)		/* get physical location */
>  #define EVIOCGUNIQ(len)		_IOC(_IOC_READ, 'E', 0x08, len)		/* get unique identifier */
> +#define EVIOCGPROP(len)		_IOC(_IOC_READ, 'E', 0x09, len)		/* get device properties */
>  
>  #define EVIOCGKEY(len)		_IOC(_IOC_READ, 'E', 0x18, len)		/* get global key state */
>  #define EVIOCGLED(len)		_IOC(_IOC_READ, 'E', 0x19, len)		/* get all LEDs */
> @@ -108,6 +109,18 @@ struct input_keymap_entry {
>  #define EVIOCGRAB		_IOW('E', 0x90, int)			/* Grab/Release device */
>  
>  /*
> + * Device properties and quirks
> + */
> +
> +#define INPUT_PROP_POINTER		0x00	/* needs a pointer */
> +#define INPUT_PROP_DIRECT		0x01	/* direct object manipulation */

fwiw, I think the common term for these is "direct input devices", at least
that's how a lot of the research literature refers to them. Might be good to
use the same term.

either way, not sure about this one.  I've worked with devices that were
indirect by nature but used directly. e.g. the magic touchpad could quite
easily be used as direct input device with an top-down projector. the
decision to use it as an indirect device is a UI decision.
Likewise, some mountable direct-touch touchscreens can be used indirectly if
the touchscreen isn't mounted straight on the display. This is very much a
setup-specific property and I'm not sure about the value of this
information.

Cheers,
  Peter

> +#define INPUT_PROP_BUTTONPAD		0x02	/* has button(s) under pad */
> +#define INPUT_PROP_SEMI_MT		0x03	/* touch rectangle only */
> +
> +#define INPUT_PROP_MAX			0x1f
> +#define INPUT_PROP_CNT			(INPUT_PROP_MAX + 1)
> +
> +/*
>   * Event types
>   */
>  
> @@ -1090,6 +1103,7 @@ struct ff_effect {
>   * @phys: physical path to the device in the system hierarchy
>   * @uniq: unique identification code for the device (if device has it)
>   * @id: id of the device (struct input_id)
> + * @propbit: bitmap of device properties and quirks
>   * @evbit: bitmap of types of events supported by the device (EV_KEY,
>   *	EV_REL, etc.)
>   * @keybit: bitmap of keys/buttons this device has
> @@ -1173,6 +1187,8 @@ struct input_dev {
>  	const char *uniq;
>  	struct input_id id;
>  
> +	unsigned long propbit[BITS_TO_LONGS(INPUT_PROP_CNT)];
> +
>  	unsigned long evbit[BITS_TO_LONGS(EV_CNT)];
>  	unsigned long keybit[BITS_TO_LONGS(KEY_CNT)];
>  	unsigned long relbit[BITS_TO_LONGS(REL_CNT)];
> -- 
> 1.7.2.3
> 

Re: [RFC v2] input: Introduce device information ioctl

[Dmitry Torokhov]

On Thu, Dec 16, 2010 at 10:29:42AM +1000, Peter Hutterer wrote:
> On Wed, Dec 15, 2010 at 08:20:07PM +0100, Henrik Rydberg wrote:
> > Today, userspace sets up an input device based on the data it emits.
> > This is not always enough; a tablet and a touchscreen may emit exactly
> > the same data, for instance, but the former should be set up with a
> > pointer whereas the latter does not need to. Recently, a new type of
> > touchpad has emerged where the buttons are under the pad, which
> > changes handling logic without changing the emitted data. This patch
> > introduces a new ioctl, EVIOCGPROP, which enables user access to a set
> > of device properties useful during setup. The properties are given as
> > a bitmap in the same fashion as the event types.
> > 
> > Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
> > ---
> > Hi all,
> > 
> > Here is version two of the device information proposal. In addition to
> > implementing the feedback, this version only defines a single combined
> > type/capabilities field. Since we want to support a device being of
> > multiple types, it suggests that we are really after the properties
> > that make up a type, rather than the types themselves. And since
> > quirks are also properties, we end up with a single bitmap of
> > properties instead.
> > 
> > As an example of how this would work for the
> > touchpad/tablet/touchscreen triplet, there are two properties defined,
> > INPUT_PROP_POINTER and INPUT_PROP_DIRECT. A touchpad is an indirect
> > pointer device, a tablet is a direct pointer device, and the
> > touchscreen is simply a direct device.
> > 
> > What do you think?
> > 
> > Thanks,
> > Henrik
> > 
> > PS. As before, the patch compiles, but is not further tested.
> > 
> >  drivers/input/evdev.c |    4 ++++
> >  drivers/input/input.c |    2 ++
> >  include/linux/input.h |   16 ++++++++++++++++
> >  3 files changed, 22 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> > index e3f7fc6..0cd97e8 100644
> > --- a/drivers/input/evdev.c
> > +++ b/drivers/input/evdev.c
> > @@ -677,6 +677,10 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
> >  #define EVIOC_MASK_SIZE(nr)	((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
> >  	switch (EVIOC_MASK_SIZE(cmd)) {
> >  
> > +	case EVIOCGPROP(0):
> > +		return bits_to_user(dev->propbit, INPUT_PROP_MAX,
> > +				    size, p, compat_mode);
> > +
> >  	case EVIOCGKEY(0):
> >  		return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);
> >  
> > diff --git a/drivers/input/input.c b/drivers/input/input.c
> > index 37708d1..ac751ce 100644
> > --- a/drivers/input/input.c
> > +++ b/drivers/input/input.c
> > @@ -1409,6 +1409,7 @@ INPUT_DEV_CAP_ATTR(LED, led);
> >  INPUT_DEV_CAP_ATTR(SND, snd);
> >  INPUT_DEV_CAP_ATTR(FF, ff);
> >  INPUT_DEV_CAP_ATTR(SW, sw);
> > +INPUT_DEV_CAP_ATTR(INPUT_PROP, prop);
> >  
> >  static struct attribute *input_dev_caps_attrs[] = {
> >  	&dev_attr_ev.attr,
> > @@ -1420,6 +1421,7 @@ static struct attribute *input_dev_caps_attrs[] = {
> >  	&dev_attr_snd.attr,
> >  	&dev_attr_ff.attr,
> >  	&dev_attr_sw.attr,
> > +	&dev_attr_prop.attr,
> >  	NULL
> >  };
> >  
> > diff --git a/include/linux/input.h b/include/linux/input.h
> > index b3a1e02..53d6364 100644
> > --- a/include/linux/input.h
> > +++ b/include/linux/input.h
> > @@ -91,6 +91,7 @@ struct input_keymap_entry {
> >  #define EVIOCGNAME(len)		_IOC(_IOC_READ, 'E', 0x06, len)		/* get device name */
> >  #define EVIOCGPHYS(len)		_IOC(_IOC_READ, 'E', 0x07, len)		/* get physical location */
> >  #define EVIOCGUNIQ(len)		_IOC(_IOC_READ, 'E', 0x08, len)		/* get unique identifier */
> > +#define EVIOCGPROP(len)		_IOC(_IOC_READ, 'E', 0x09, len)		/* get device properties */
> >  
> >  #define EVIOCGKEY(len)		_IOC(_IOC_READ, 'E', 0x18, len)		/* get global key state */
> >  #define EVIOCGLED(len)		_IOC(_IOC_READ, 'E', 0x19, len)		/* get all LEDs */
> > @@ -108,6 +109,18 @@ struct input_keymap_entry {
> >  #define EVIOCGRAB		_IOW('E', 0x90, int)			/* Grab/Release device */
> >  
> >  /*
> > + * Device properties and quirks
> > + */
> > +
> > +#define INPUT_PROP_POINTER		0x00	/* needs a pointer */
> > +#define INPUT_PROP_DIRECT		0x01	/* direct object manipulation */
> 
> fwiw, I think the common term for these is "direct input devices", at least
> that's how a lot of the research literature refers to them. Might be good to
> use the same term.
> 
> either way, not sure about this one.  I've worked with devices that were
> indirect by nature but used directly. e.g. the magic touchpad could quite
> easily be used as direct input device with an top-down projector. the
> decision to use it as an indirect device is a UI decision.
> Likewise, some mountable direct-touch touchscreens can be used indirectly if
> the touchscreen isn't mounted straight on the display. This is very much a
> setup-specific property and I'm not sure about the value of this
> information.

All of these "props" would have no reflection on the event stream
generated by the device, and exist solely for the benefits of userspace
consumers to help them set up the device automatically and interpret the
data appropriately. As such, if someone uses touchscreen as a tablet, I
believe userspace should allow it, but at the price of manual setup.

If we start seeing cuch devices we could consider EVIOCSPROPS so
infrastructure (udev) could adjust the properties so that upper levels
(X) can still use the data to set up devices properly.

What do you think?

-- 
Dmitry

Re: [RFC v2] input: Introduce device information ioctl

[Henrik Rydberg]

>>> As an example of how this would work for the

>>> touchpad/tablet/touchscreen triplet, there are two properties defined,
>>> INPUT_PROP_POINTER and INPUT_PROP_DIRECT. A touchpad is an indirect
>>> pointer device, a tablet is a direct pointer device, and the
>>> touchscreen is simply a direct device.
>>>
>>> What do you think?
>>
>> I must have missed the first version of this patch, but I give two
>> thumbs way up :). The detection code for touchpad/tablet/touchscreen in
>> xf86-input-evdev is large and unwieldy, and seemingly simple changes to
>> an input driver can cause incorrect interpretation. Having this
>> available should help quite a bit!
>>
>> Acked-by: Chase Douglas <chase.douglas@canonical.com>
> 
> As long as we document that !pointer && !direct means "unknown" or
> "unspecified" so as to avoid having to update all devices at once that
> should be OK.
> 
> We also need to wire up uinput.


Great, will cook a proper patch.

Thanks,
Henrik

Re: [RFC v2] input: Introduce device information ioctl

[Henrik Rydberg]

>>>  /*

>>> + * Device properties and quirks
>>> + */
>>> +
>>> +#define INPUT_PROP_POINTER		0x00	/* needs a pointer */
>>> +#define INPUT_PROP_DIRECT		0x01	/* direct object manipulation */
>>
>> fwiw, I think the common term for these is "direct input devices", at least
>> that's how a lot of the research literature refers to them. Might be good to
>> use the same term.
>>
>> either way, not sure about this one.  I've worked with devices that were
>> indirect by nature but used directly. e.g. the magic touchpad could quite
>> easily be used as direct input device with an top-down projector. the
>> decision to use it as an indirect device is a UI decision.
>> Likewise, some mountable direct-touch touchscreens can be used indirectly if
>> the touchscreen isn't mounted straight on the display. This is very much a
>> setup-specific property and I'm not sure about the value of this
>> information.
> 
> All of these "props" would have no reflection on the event stream
> generated by the device, and exist solely for the benefits of userspace
> consumers to help them set up the device automatically and interpret the
> data appropriately. As such, if someone uses touchscreen as a tablet, I
> believe userspace should allow it, but at the price of manual setup.
> 
> If we start seeing cuch devices we could consider EVIOCSPROPS so
> infrastructure (udev) could adjust the properties so that upper levels
> (X) can still use the data to set up devices properly.
> 
> What do you think?
> 


I am not 100% convinced. If other things like touchscreen orientation would fit
into that flow as well, then I'd say yes. But if there will always be a
difference between a default device setting and a system-wide device setting,
then it seems reasonable to handle this in userspace.

Henrik

Re: [RFC v2] input: Introduce device information ioctl

[Henrik Rydberg]

>>  /*
>> + * Device properties and quirks
>> + */
>> +
>> +#define INPUT_PROP_POINTER		0x00	/* needs a pointer */
>> +#define INPUT_PROP_DIRECT		0x01	/* direct object manipulation */
> 
> fwiw, I think the common term for these is "direct input devices", at least
> that's how a lot of the research literature refers to them. Might be good to
> use the same term.


Changed, thanks.


> either way, not sure about this one.  I've worked with devices that were
> indirect by nature but used directly. e.g. the magic touchpad could quite
> easily be used as direct input device with an top-down projector. the
> decision to use it as an indirect device is a UI decision.
> Likewise, some mountable direct-touch touchscreens can be used indirectly if
> the touchscreen isn't mounted straight on the display. This is very much a
> setup-specific property and I'm not sure about the value of this
> information.


As Dmitry stated already, this is foremost for automatic setup. The idea to
elevate these properties to the main configuration source is also interesting.

Thanks,
Henrik

Re: [RFC v2] input: Introduce device information ioctl

[Peter Hutterer]

[sorry, mail stuck in my outbox for some reason]

On Wed, Dec 15, 2010 at 04:43:58PM -0800, Dmitry Torokhov wrote:
> On Thu, Dec 16, 2010 at 10:29:42AM +1000, Peter Hutterer wrote:
> > >  
> > >  /*
> > > + * Device properties and quirks
> > > + */
> > > +
> > > +#define INPUT_PROP_POINTER		0x00	/* needs a pointer */
> > > +#define INPUT_PROP_DIRECT		0x01	/* direct object manipulation */
> > 
> > fwiw, I think the common term for these is "direct input devices", at least
> > that's how a lot of the research literature refers to them. Might be good to
> > use the same term.
> > 
> > either way, not sure about this one.  I've worked with devices that were
> > indirect by nature but used directly. e.g. the magic touchpad could quite
> > easily be used as direct input device with an top-down projector. the
> > decision to use it as an indirect device is a UI decision.
> > Likewise, some mountable direct-touch touchscreens can be used indirectly if
> > the touchscreen isn't mounted straight on the display. This is very much a
> > setup-specific property and I'm not sure about the value of this
> > information.
> 
> All of these "props" would have no reflection on the event stream
> generated by the device, and exist solely for the benefits of userspace
> consumers to help them set up the device automatically and interpret the
> data appropriately. As such, if someone uses touchscreen as a tablet, I
> believe userspace should allow it, but at the price of manual setup.
> 
> If we start seeing cuch devices we could consider EVIOCSPROPS so
> infrastructure (udev) could adjust the properties so that upper levels
> (X) can still use the data to set up devices properly.
> 
> What do you think?

I figured it didn't have any effect on the data stream.
I think that for 95% of the devices, this information will probably be
correct and the only ones affected are rather exotic setups anyway that need
special setup. so I don't really oppose the flag, but there should be
documentation on what it means and that it only represents the assumed usage
of the device.

Cheers,
  Peter