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

Mauro Carvalho Chehab
2010-03-30T12:43:53Z

David Härdeman wrote:
> On Sun, Mar 28, 2010 at 08:22:31PM -0300, Mauro Carvalho Chehab wrote:
>> I also noticed another problem: kernel should have some way to report
>> the expected
>> size of the scancode to userspace, especially if we want to have the compatibility
>> code (since, with compat, a scancode maximum size need to be 32 bits, otherwise
>> the code won't work).
>>
>> I'll likely adding another control that returns the size of the scancode.
>
> And perhaps the interface should explicitly define that for the case
> where userspace sends an undersized scancode, the real scancode will be
> generated by zero-extending the undersized scancode into its expected
> size.
>
> That way the interface will be binary-forwards-compatible even if
> scancode sizes are increased at some later date.

Makes sense. Padding an undersized scancode is endian-dependent. So, we'll
likely need to add some padding functions. The better seems to add the logic
at include/linux/byteorder/generic.h.

--

Cheers,
Mauro