Re: [PATCH] media: rc: gpio-ir-recv: add QoS support for cpuidle system

[Sean Young <sean@mess.org>]

Hi Joakim,

On Wed, Sep 16, 2020 at 10:22:11AM +0000, Joakim Zhang wrote:
> 
> Hi Sean,
> 
> Thanks for your hint, I will send a V2 soon according to your suggestions.
> 
> We also have a concern, since you are a IR expert, may you can give us answers. With this patch, the first frame once press could not been decoded.
> AFAIK, IR protocols have not specify how may frames transmitting once press, is there ang criterion to decide this?
> 
> Is it possible that single frame transmitting once pressing? Per my understanding, it will transmit more than one frame.

So remotes send IR signals while a button is being pressed down. For the
remotes I've seen, when pressing a button a short amount of time will repeat
the IR message at least three times. This is a few times when I've tried
this, but by no means exhaustive of all remotes or protocols.

I think the question you are trying to answer is, if we miss the first
message, will we at least have another chance if the message is repeated?

So I think the message will be repeated, but the repeat message is not
enough for the nec protocol. The nec repeat is a shorter message which
does not carry any information apart from "last key still pressed":

https://www.sbprojects.net/knowledge/ir/nec.php

Thanks,

Sean