Re: uinput question

From: Dmitry Torokhov
Date: Fri Apr 25 2008 - 14:26:31 EST


Hi Yan,

On Sun, Apr 20, 2008 at 04:32:36PM -0700, Yan Seiner wrote:
> I'm trying to set up a system with multiple IR remotes acting as keyboards
> for specific X sessions.
>
> lirc <http://www.lirc.org> is a way to send infrared remote keystrokes to
> applications. Some time ago I wrote a small patch to kbdd
> <http://handhelds.org/moin/moin.cgi/kbdd> that lets me inject button pushes
> on an IR remote into the /dev/input/uinput system as keyboard events.
>
> Now I'd like to send those keyboard events to only one X session, not all
> of them.
>
> In the kbdd code, there is the following snippet when the /dev/input/uinput
> device is opened:
>
> memset(&dev, 0, sizeof(dev));
> strncpy(dev.name, "SerKBD", UINPUT_MAX_NAME_SIZE);
> dev.idbus = BUS_RS232;
> dev.idvendor = 0x00;
> dev.idproduct = 0x00;
> dev.idversion = 0x00;
>
> So this would indicate to me that I can emulate different devices by
> changing the names, IDs, and events. Then I want to select only those
> events that pertain to my app...
> So...
> - Create a 'virtual' eventNN device based on the data fed to kbdd
> - Send various keyboard events to the kernel via the uinput device from
> several physical devices
> - Select only those events destined for my virtual device
> - Have those events pop out of my eventNN device so I can handle them
> back in userspace
>

You would need to set up uinput instance for every set of remotes you
want to send events to a particular X instance and then make X use
evdev driver to listen to the input events coming from 'their'
/dev/input/eventXX. You may need to teach X not to release event
device when switching vts so events from the uinput-connected devices
never reach the standard consolde driver.

Hope this helps.

--
Dmitry
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