Re: [PATCH] Documented input device properties.

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:

quoted

---
 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.)

quoted

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