[PATCH] Documented input device properties.

[PATCH] Documented input device properties.

[Jussi Pakkanen]

---
 Documentation/input/event-codes.txt |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/Documentation/input/event-codes.txt b/Documentation/input/event-codes.txt
index 23fcb05..7c515a5 100644
--- a/Documentation/input/event-codes.txt
+++ b/Documentation/input/event-codes.txt
@@ -220,6 +220,33 @@ EV_PWR:
 EV_PWR events are a special type of event used specifically for power
 mangement. Its usage is not well defined. To be addressed later.
 
+Device properties:
+=================
+
+INPUT_PROP_POINTER:
+------------------
+There is a one to one mapping between the device coordinates and
+screen coordinates. This property only has meaning for non-touch based
+input such as a pen or an eraser. A drawing tablet would have this property
+set.
+INPUT_PROP_DIRECT:
+------------------
+The same as INPUT_PROP_POINTER, but for touches. An example would be a
+touchscreen.
+INPUT_PROP_BUTTONPAD:
+--------------------
+The device has one or more physical buttons beneath the active surface area.
+This means that you can generate button clicks by pressing down on the
+trackpad area. Examples include aluminium body MacBook trackpads and 
+Synaptics clickpads.
+INPUT_PROP_SEMI_MT:
+------------------
+The device is a semi multitouch device. This means that it does not
+provide proper touch locations; it only reports the total number of
+touches and a bounding box that is defined by two of the
+touches. There is no way to know which two touches the device chooses
+to report.
+
 Guidelines:
 ==========
 The guidelines below ensure proper single-touch and multi-finger functionality.
-- 
1.7.5.4

Re: [PATCH] Documented input device properties.

[Dmitry Torokhov]

Hi Jussi,

On Mon, Jan 09, 2012 at 06:44:14PM +0200, Jussi Pakkanen wrote:
> ---
>  Documentation/input/event-codes.txt |   27 +++++++++++++++++++++++++++
>  1 files changed, 27 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/input/event-codes.txt b/Documentation/input/event-codes.txt
> index 23fcb05..7c515a5 100644
> --- a/Documentation/input/event-codes.txt
> +++ b/Documentation/input/event-codes.txt
> @@ -220,6 +220,33 @@ EV_PWR:
>  EV_PWR events are a special type of event used specifically for power
>  mangement. Its usage is not well defined. To be addressed later.
>  
> +Device properties:
> +=================
> +
> +INPUT_PROP_POINTER:
> +------------------
> +There is a one to one mapping between the device coordinates and
> +screen coordinates.

This is not correct as touchpads fall firmly into INPUT_PROP_POINTER
land and certainly do not have 1:1 relationship between on-screen and
device coordinates.

> This property only has meaning for non-touch based
> +input such as a pen or an eraser. A drawing tablet would have this property
> +set.

Wacom Bamboo touch can be said is touch based but still is a pointer
device. Basically pointer device is one that requires use of an
on-screen pointer to reflect user's movement while with direct devices
touching object itself serves as a pointer to the user.

Thanks.

-- 
Dmitry

Re: [PATCH] Documented input device properties.

[Chase Douglas]

On 01/09/2012 06:55 PM, Dmitry Torokhov wrote:
> Hi Jussi,
> 
> On Mon, Jan 09, 2012 at 06:44:14PM +0200, Jussi Pakkanen wrote:
>> ---
>>  Documentation/input/event-codes.txt |   27 +++++++++++++++++++++++++++
>>  1 files changed, 27 insertions(+), 0 deletions(-)
>>
>> diff --git a/Documentation/input/event-codes.txt b/Documentation/input/event-codes.txt
>> index 23fcb05..7c515a5 100644
>> --- a/Documentation/input/event-codes.txt
>> +++ b/Documentation/input/event-codes.txt
>> @@ -220,6 +220,33 @@ EV_PWR:
>>  EV_PWR events are a special type of event used specifically for power
>>  mangement. Its usage is not well defined. To be addressed later.
>>  
>> +Device properties:
>> +=================
>> +
>> +INPUT_PROP_POINTER:
>> +------------------
>> +There is a one to one mapping between the device coordinates and
>> +screen coordinates.
> 
> This is not correct as touchpads fall firmly into INPUT_PROP_POINTER
> land and certainly do not have 1:1 relationship between on-screen and
> device coordinates.

Yeah, the definition of this should be inverted. (This is my mistake, as
I gave Jussi the wrong definition when he was writing this up.)

>> This property only has meaning for non-touch based
>> +input such as a pen or an eraser. A drawing tablet would have this property
>> +set.
> 
> Wacom Bamboo touch can be said is touch based but still is a pointer
> device. Basically pointer device is one that requires use of an
> on-screen pointer to reflect user's movement while with direct devices
> touching object itself serves as a pointer to the user.

This definition, while usually correct, is mixing properties and policy.
We had a discussion about this:

http://thread.gmane.org/gmane.linux.kernel.input/21565/focus=21658

The definitions in this patch try to reflect the outcome of that discussion.

-- Chase