Re: [PATCH v3 0/7] Support inhibiting input devices

From: Pavel Machek <pavel@ucw.cz>
To: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Cc: linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-input@vger.kernel.org,
	linux-tegra@vger.kernel.org, patches@opensource.cirrus.com,
	ibm-acpi-devel@lists.sourceforge.net,
	platform-driver-x86@vger.kernel.org,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>, Jonathan Cameron <jic23@kernel.org>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	Kukjin Kim <kgene@kernel.org>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
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	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Vladimir Zapolskiy <vz@mleia.com>,
	Sylvain Lemieux <slemieux.tyco@gmail.com>,
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	Jonathan Hunter <jonathanh@nvidia.com>,
	Barry Song <baohua@kernel.org>,
	Michael Hennerich <michael.hennerich@analog.com>,
	Nick Dyer <nick@shmanahar.org>,
	Hans de Goede <hdegoede@redhat.com>,
	Ferruh Yigit <fery@cypress.com>, Sangwon Jee <jeesw@melfas.com>,
	Peter Hutterer <peter.hutterer@redhat.com>,
	Henrique de Moraes Holschuh <ibm-acpi@hmh.eng.br>,
	kernel@collabora.com
Subject: Re: [PATCH v3 0/7] Support inhibiting input devices
Date: Sun, 7 Jun 2020 22:24:14 +0200	[thread overview]
Message-ID: <20200607202414.GB13138@amd> (raw)
In-Reply-To: <20200605173335.13753-1-andrzej.p@collabora.com>

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On Fri 2020-06-05 19:33:28, Andrzej Pietrasiewicz wrote:
> Userspace might want to implement a policy to temporarily disregard input
> from certain devices.

Wow, you certainly cc a lot of lists.

> An example use case is a convertible laptop, whose keyboard can be folded
> under the screen to create tablet-like experience. The user then must hold
> the laptop in such a way that it is difficult to avoid pressing the keyboard
> keys. It is therefore desirable to temporarily disregard input from the
> keyboard, until it is folded back. This obviously is a policy which should
> be kept out of the kernel, but the kernel must provide suitable means to
> implement such a policy.
> 
> Due to interactions with suspend/resume, a helper has been added for drivers
> to decide if the device is being used or not (PATCH 1/7) and it has been
> applied to relevant drivers (PATCH 2,4,5,6/7).

But is that a right way to implement it?

We want this for cellphones, too -- touchscreen should be disabled
while the device is locked in the pocket -- but we really want the
touchscreen hardware to be powered down in that case (because it keeps
SoC busy and eats a _lot_ of electricity).

But simplistic "receive an event and then drop it if device is
inhibited" does not allow that...

Best regards,
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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