Re: [PATCH 2/4] Input: introduce ABS_MAX2/CNT2 and friends

From: Dmitry Torokhov
Date: Wed Dec 18 2013 - 11:36:39 EST


On Wed, Dec 18, 2013 at 03:44:48PM +0100, David Herrmann wrote:
> >>
> >> /*
> >> + * Due to API restrictions the legacy evdev API only supports ABS values up to
> >> + * ABS_MAX/CNT. Use the extended *ABS2 ioctls to operate on any ABS values in
> >> + * between ABS_MAX and ABS_MAX2.
> >> + */
> >> +#define ABS_MAX2 0x3f
> >> +#define ABS_CNT2 (ABS_MAX2+1)
> >> +
> >
> > Maybe it's just my English, but when you say "between ABS_MAX and
> > ABS_MAX2" it sounds like the old protocol still _must_ be used for
> > values <= ABS_MAX.
> >
> > IIUC this is true "only" for compatibility with older kernels right?
> > If a program decides to support only newer kernels it can check the
> > protocol version and use only the new ioctls, right?
> >
> > Maybe you can be more explicit about that in the comment?
>
> See the comment on "struct input_absinfo2". It describes the API, this
> comment just describes the ABS_* values. But if anyone has a better
> phrase to use here, I will gladly adjust it.

"Use the extended *ABS2 ioctls to access the full range of ABS values
supported by the kernel."

?

--
Dmitry
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