Re: [PATCH v4] platform/x86: ideapad-laptop: Add sysfs interface for touchpad state

From: Ritesh Raj Sarraf
Date: Mon May 01 2017 - 14:28:11 EST


On Mon, 2017-05-01 at 09:05 -0700, Darren Hart wrote:
> > sysfs ABI for drivers that provide input interface is quite strong for
> > my opinion. It means I'm not totally objecting, but I would accept it
> > if and only if there is nothing else could be done.
>
> Agreed, we've recently wanted to remove certain sysfs attributes from another
> driver as they were obsolete and better implemented in other ways, but once
> they
> are there, are hands are tied.
>
> That said, we will support getting these systems functional. From what I see
> in
> the patch you are implementing a polling sysfs interface. Have you verified
> that
> there is no event we can capture and send the SW_TABLET_MODE along to the
> input
> system?

I believe it does generate an event (at least on my Yoga 2 13 variant). IIRC,
when I talked to Andy initially about the driver's limitation, we did do an
exercise [1] to determine if an event was generated.

Cooking this patch (sysfs interface) was much quicker and easy. I looked at the
other example drivers, that do SW_TABLET_MODE, but left it there. I don't think
I have all the necessary information to get that done for the ideapad driver.


[1] https://patchwork.kernel.org/patch/9546987/

--
Ritesh Raj Sarraf | http://people.debian.org/~rrs
Debian - The Universal Operating System

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