Re: [PATCH 1/2] drm/input_helper: Add new input-handling helper

From: Dmitry Torokhov
Date: Wed Nov 17 2021 - 15:47:52 EST


On Wed, Nov 17, 2021 at 10:38:58AM -0800, Brian Norris wrote:
> On Fri, Nov 12, 2021 at 4:52 PM Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
>
> (Snip other comments; they seem reasonable, and I'll factor them into
> the next version)
>
> > I guess one random thought I had is whether there would be an
> > appropriate place to put this that _wasn't_ in DRM. I still wonder
> > whether we'll ever try to upstream something like the cpufreq boost
> > driver that we're carrying around and using in Chrome OS. If so, it
> > would want to use these same helpers and it'd be pretty awkward for it
> > to have to reach into DRM. ...any chance we could just land these
> > helpers somewhere more generic?
>
> Yeah, I was torn on what to do here as well. I'd rather land something
> than nothing, and when reading past conversations, it sounded like
> Dmitry didn't want this kind of thing in drivers/input/ [1]. I'd love
> to be wrong here though.

I simply feel that input_handler is already a very simple abstraction
and trying to specialize it to simplify users further is not productive.

>
> I'm not sure where else this would belong though -- either in the
> producing subsystem (input) or the consuming one(s) (drm, cpufreq). We
> could make up some odd middle ground I suppose (lib/?), but that seems
> pretty artificial.
>
> I guess one question is, what is this abstracting, and is that
> abstraction actually a shared need for multiple subsystems? I think
> the abstraction is, "impending user activity; <component X> should
> prepare itself". That general need is exactly the same for the cases
> I'm aware of. And if there is any tuning needed (e.g., ignore input
> device Y; or turn the whole thing off, because we're ignoring input
> for now), that would also seem to be a shared need.
>
> Anyway, back to my first paragraph: I'll plan on keeping this as-is
> (as a DRM helper) unless I hear otherwise from input folks.
>
> Brian
>
> [1] https://lore.kernel.org/all/20180416174117.GA77055@dtor-ws/

Thanks.

--
Dmitry