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

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Brian Norris <briannorris@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Andrzej Hajda <andrzej.hajda@intel.com>,
	linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
	David Airlie <airlied@linux.ie>,
	linux-rockchip@lists.infradead.org,
	"Kristian H . Kristensen" <hoegsberg@google.com>,
	Rob Clark <robdclark@chromium.org>,
	Rob Clark <robdclark@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH 1/2] drm/input_helper: Add new input-handling helper
Date: Wed, 17 Nov 2021 12:47:41 -0800	[thread overview]
Message-ID: <YZVqbZpAPHOBG6bL@google.com> (raw)
In-Reply-To: <CA+ASDXMvZCjn+X98JccyJiLQ0ggq-t-HqnM5SKYMbiQFqZDhGQ@mail.gmail.com>

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@chromium.org> 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