Android on OMAP
|2011-09-04 05:23:31||Re: [Omapandroid-discussion] Omapandroid-discussion Digest, Vol 38,Issue 1|
|Posted By: Amit Pundir|
Join Date: 2009-09-11
|On Fri, Sep 2, 2011 at 1:24 AM, wiiNinja
> Thanks for your response. If I may ask a follow up question:
> I am looking at a current touchscreen driver for the Blaze
> "qtouch_obp_ts.c" and it reports the following events:
> ABS_MT_TOUCH_MAJOR, ABS_MT_WIDTH_MAJOR, ABS_MT_POSITION_X,
> ABS_MT_POSITION_Y, ABS_MT_TRACKING_ID.
> I don't see the ABS_MT_PRESSURE event being reported by this driver. So my
> question is if Android expects and require this ABS_MT_PRESSURE event to be
> sent? In the case where the touchscreen hardware does not have support for
> pressure, how should that be handled by the device driver?
>From Android layer, here is the function which handle the touch events being
reported by the TS driver
I have not worked on TS drivers as such. So I'm not sure if it is mandatory
for a TS driver to report Pressure or Width values but Android does
initialise Pressure and Width values to '0' for the devices which do not
report those values. See the SingleTouchInputMapper Class functions for
>> On Wed, Aug 31, 2011 at 11:01 PM, wiiNinja
>> > Hello everyone,
>> > I'm trying to educate myself from the bottom up. So I learned that when
>> > comes to the touchscreen, Android requires the kernel's input subsystem
>> > provide 5 events: x coordinate, y coordinate, pressure, penup, pendown.
>> > This is made available by the driver in the user space through
>> > /dev/input/event*. I am trying to find out which entity is actually
>> > use of this interface to provide the input to the upper layers.
>> > Specifically, is there a HAL library or some native Linux code which use
>> > that interface?
>> > Thanks in advance for any insight.
>> Input interfaces e.g. /dev/input/event* are exposed to Android User space
>> through EventHub (frameworks/base/libs/ui/EventHub.cpp).
>> Complete native Event handling support (Input Reader, Dispatcher etc) is
>> implemented in libui.so (frameworks/base/libs/ui/*).
>> Amit Pundir
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