Re: [PATCH][resend] rc: gpio-ir-recv: allow flush space on idle

[Eric Nelson <eric@nelint.com>]

Thanks Shawn,

On 09/14/2015 03:00 AM, Sean Young wrote:
> On Fri, Sep 11, 2015 at 07:00:24AM -0700, Eric Nelson wrote:
>> Many decoders require a trailing space (period without IR illumination)
>> to be delivered before completing a decode.
>>
>> Since the gpio-ir-recv driver only delivers events on gpio transitions,
>> a single IR symbol (caused by a quick touch on an IR remote) will not
>> be properly decoded without the use of a timer to flush the tail end
>> state of the IR receiver.
> 
> This is a problem other IR drivers suffer from too. It might be better
> to send a IR timeout event like st_rc_send_lirc_timeout() in st_rc.c,
> with the duration set to what the timeout was. That is what irraw 
> timeouts are for; much better than fake transitions.
> 

If I'm understanding this correctly, this would require modification
of each decoder to handle what seems to be a special case regarding
the GPIO IR driver (which needs an edge to trigger an interrupt).

Isn't it better to have the device interface handle this in one place?

>> This patch adds an optional device tree node "flush-ms" which, if
>> present, will use a jiffie-based timer to complete the last pulse
>> stream and allow decode.
> 
> A common value for this is 100ms, I'm not sure what use it has to have
> it configurable. It's nice to have it exposed in rc_dev->timeout.
> 

I'm enough of a n00b regarding the details of the various decoders
not to know that...

I looked through the couple of decoders my customer was using (NEC and
RC6) and came up with a value of 100ms though...

Implementing this through DT and having the default as 0 (disabled)
provides an interim solution if the choice is made to change each of
the decoders, since I would expect that to take a while and a bunch of
remote control devices for testing.

Regards,


Eric