On Wed, Nov 25, 2009 at 03:28:54PM +0200, Maxim Levitsky wrote:

On Tue, 2009-11-24 at 19:32 -0800, Trent Piepho wrote: 

quoted

On Wed, 25 Nov 2009, Maxim Levitsky wrote:

quoted

Its not the case.
There are many protocols, I know that by experimenting with my universal
remote. There are many receivers, and all have different accuracy.
Most remotes aren't designed to be used with PC, thus user has to invent
mapping between buttons and actions.
Its is not possible to identify remotes accurately, many remotes send
just a 8 bit integer that specifies the 'model' thus many remotes can
share it.

The signal recevied by the ir receiver contains glitches.  Depending on the
receiver there can be quite a few.  It is also not trivial to turn the raw
signal sent by the remote into a digital value, even if you know what to
expect.  It takes digital signal processing techniques to turn the messy
sequence of inaccurate mark and space lengths into a best guess at what
digital code the remote sent.

Exactly

quoted

It's like turning raw VBI data into decoded ASCII teletext from a simulated
keyboard device, all in the kernel.

You hit a nail on the head with this one.

Absolutely. There are a number of use cases when you want access to the 
space-pulse (i.e. IR) information. For debugging purposes; support for 
non-standard remotes. Being able to do a precise recording of IR activity
so you can replay without parsing. One could even imagine IR being used 
for completely different purposes than "key strokes", so the kernel
should not enforce this "policy".

In the past I've spent time dissecting the IR output of a strange remote, 
I would hate to think this would not be possible due to mad kernel 
interfaces which cater just for drooling in front of the telly with
your *new* remote.


Sean