[mythtv-users] Why does my USB IR remote behave like a keyboard?

David Watkins watkinshome at gmail.com
Tue Jan 31 08:55:10 UTC 2006

On 30/01/06, Joseph A. Caputo <jcaputo1 at comcast.net> wrote:
> On Monday 30 January 2006 14:41, Richard Bronosky wrote:
> > I'm trying to debug my remote, but I know nothing about LIRC.  So my
> > first step in understanding what is happening is to figure out why my
> > remote behaves like a keyboard.  I checked dmesg and the USB receiver
> > that came with the remote is detected as a Philips RCS Keyboard.  It
> > has a HID an everything.  Many of the buttons are returning normal
> > keycodes.  Many are not.  I want to get to a point where I can get a
> > signal from each of the buttons, then I can do something with the
> > signal.
> >
> > So, does LIRC cause a remote to look like a keyboard?
> No.
> > Or, do you
> > think the USB receiver for the remote is designed to appear to be a
> > keyboard?
> Yes.  You don't need LIRC here, you need to figure out how to configure
> your keyboard settings to recognize the keycodes your remote is
> sending.

I did this for my nova-t remote by editing one of the module files,
cx88_input.c IIRC.

This file just mapped remote keypresses onto keyboard codes defined in
input.h.  for some reason almost all of them either didn't exist or
were different to those used by the keyboard driver.

There was a lot of trial and error involved on my part because:

1)     I didn't know what I was doing.
2)     There were mapping tables for several different remotes in that
file (and others in other modules) and I couldn't work out what
determined which one was being used.
3)     Some of the non-working buttons generated dmesg errors, which
indicated which row in the table needed to be changed, but others
failed silently.

The evtest programme was useful, if I remember right.

Once I got the hang of it, it was fairly straightforward to map all
the buttons to the keypresses that mythtv uses.  However the key
repeat rate was much too fast and I ended up running lirc on top of
the event driver, just to control the repeat speed.

Not sure if any of this will help you with your usb receiver.  The
only reason I was able to do it was because I'd spent a week learning
how to compile kernels in order to patch my dvb modules, which didn't
work out of the box back in the days of the 2.6.11 kernel.

Good Luck

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