Re: [RFC] What are the goals for the architecture of an in-kernel IR system?

Mauro Carvalho Chehab
2009-12-01T13:12:07Z

Gerd Hoffmann wrote:
> On 11/30/09 13:34, Mauro Carvalho Chehab wrote:
>> Christoph Bartelmus wrote:
>>> Hi Mauro,
>>>
>>> I just don't want to change a working interface just because it could be
>>> also implemented in a different way, but having no other visible
>>> advantage
>>> than using more recent kernel features.
>>
>> I agree. The main reasons to review the interface is:
>> 1) to avoid any overlaps (if are there any) with the evdev interface;
>
> Use lirc for raw samples.
> Use evdev for decoded data.
>
> Hardware/drivers which can handle both can support both interfaces.
> IMHO it makes no sense at all to squeeze raw samples through the input
> layer. It looks more like a serial line than a input device. In fact
> you can homebrew a receiver and connect it to the serial port, which was
> quite common in pre-usb-ir-receiver times.

I agree.
>
>> 2) to have it stable enough to be used, without changes, for a long
>> time.
>
> It isn't like lirc is a new interface. It has been used in practice for
> years. I don't think API stability is a problem here.

You're probably right here, but, as, currently, changing the API is not a problem,
I don't doubt that the API has changed during those years (I haven't followed
lirc API, so this is just an educated guess).

So, all I'm saying is that we should do a final review considering API stability
before merging it, eventually considering to add a few reserved fields there, if
we suspect that we might need more space for some reason.

>> True, but even if we want to merge lirc drivers "as-is", the drivers will
>> still need changes, due to kernel CodingStyle, due to the usage of
>> some API's
>> that may be deprecated, due to some breakage with non-Intel
>> architectures, due
>> to some bugs that kernel hackers may discover, etc.
>
> I assumed this did happen in already in preparation of this submission?

Yes, for just a few drivers that went on the first series of patches (on Jerod's
proposal, only 2 drivers were submitted).

Cheers,
Mauro.