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

From: Andy Shevchenko
Date: Fri Feb 17 2017 - 02:39:36 EST

On Fri, Feb 17, 2017 at 5:33 AM, Darren Hart <dvhart@xxxxxxxxxxxxx> wrote:
> On Tue, Feb 14, 2017 at 07:46:12PM +0530, Ritesh Raj Sarraf wrote:
>> Lenovo Yoga (many variants: Yoga, Yoga2 Pro, Yoga2 13, Yoga3 Pro, Yoga 3
>> 14 etc) has multiple modles that are a hybrid laptop, working in laptop
>> mode as well as tablet mode.

> That said, we need to make these systems usable, and as there appears not to be
> an accepted standard way of doing this, I don't object to the approach. However,
> you mentioned in the bug comments (#64) on 2/12:
> "I have attached the final patch that I had proposed, but for whatever
> reasons, the maintainer isn't convinced that that interface is needed."
> This is the only version of this patch I have seen.

This patch is actually a v2 that includes maintainers as I had asked
and additional paragraph to explain why we need such interface.

> Who objected to the patch?

I was trying to understand why /dev/input/eventX can not be used for a such.

> I would like to hear from Rafael and Dmitry, for their opinion on an ACPI or INPUT
> interface for indicating TABLET_MODE to userspace. Even if we accept this patch
> as is, we should be thinking about how to do this in a standard way.

Good point!

>> +
>> + if (!count)
>> + return 0;
>> + if (sscanf(buf, "%i", &state) != 1)
>> + return -EINVAL;
> Please use kstrtoint, and no need to check for count as this function won't get
> called if it is 0.

I guess Ritesh followed existing style in the code.

With Best Regards,
Andy Shevchenko