Re: [RFC] input: syfs switches for SKE keypad

Ferenc Wagner
2010-10-13T17:35:49Z

Pavel Machek <pavel@ucw.cz> writes:

>> For mobile devices it is not acceptable to filter events away at some
>> upper SW layer depending on the system state. The HW which generates
>> those events may not generate events at all to allow longer CPU sleep
>> periods.
>
> Ok.
>
>> In ideal world it would be nice to control device states based on for
>> example user count. However, there are several listeners for input
>> devices and it is hard or impossible to have them all to follow overall
>> state transition (screen blanked etc.). Instead, there is some
>> system
>
> So you have mobile device; why is it impossible to just close the
> device when you do not want the events? I guess it is hard for generic
> distros, but on your phone, you should be able to modify Xserver to
> close touchscreen/keypad device when it is not needed... right?

We'd had this discussion before... cf. eg.
http://thread.gmane.org/gmane.linux.kernel.input/9266/focus=9767

The problem was that several processes may have a device open, while
another process should be able to control the state of the device.
Maybe this could be solved by making the controlling process a proxy,
and having all "user" processes going though it. Then the controlling
(proxy) process could open/close the device as it wants, letting the
runtime PM do its job. But this would mean duplicating some kernel
functionality (at least multiplexing) in user space.
--
Regards,
Feri.