mbox series

[v3,0/7] Support inhibiting input devices

Message ID 20200605173335.13753-1-andrzej.p@collabora.com (mailing list archive)
Headers show
Series Support inhibiting input devices | expand

Message

Andrzej Pietrasiewicz June 5, 2020, 5:33 p.m. UTC 
Userspace might want to implement a policy to temporarily disregard input
from certain devices.

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).

PATCH 7/7 adds support for inhibiting input devices.

This work is inspired by:

https://chromium.googlesource.com/chromiumos/third_party/kernel/+/45c2d7bb398f74adfae0017e20b224152fde3822

and

https://chromium.googlesource.com/chromiumos/third_party/kernel/+/4ce0e8a3697edb8fd071110b3af65014512061c7

In this respin the elan_i2c patch is dropped and converting it will be
addressed later.

v2..v3:
- ignored autorepeat events in input_get_disposition() if a key is not
pressed (Hans)
- dropped inhibit()/uninhibit() driver callbacks (Hans)
- split ACPI button patch into taking the lock and using the helper (Rafael)
- dropped the elan_i2c conversion
- fixed typos in exynos adc

v1..v2:
- added input_device_enabled() helper and used it in drivers (Dmitry)
- the fact of open() and close() being called in inhibit/uninhibit paths has
been emphasized in the commit message of PATCH 6/7 (Dmitry)

Andrzej Pietrasiewicz (6):
  Input: add input_device_enabled()
  Input: use input_device_enabled()
  ACPI: button: Access input device's users under appropriate mutex
  ACPI: button: Use input_device_enabled() helper
  iio: adc: exynos: Use input_device_enabled()
  platform/x86: thinkpad_acpi: Use input_device_enabled()

Patrik Fimml (1):
  Input: Add "inhibited" property

 drivers/acpi/button.c                       |   7 +-
 drivers/iio/adc/exynos_adc.c                |  11 +-
 drivers/input/input.c                       | 121 +++++++++++++++++++-
 drivers/input/joystick/xpad.c               |   4 +-
 drivers/input/keyboard/ep93xx_keypad.c      |   2 +-
 drivers/input/keyboard/gpio_keys.c          |   4 +-
 drivers/input/keyboard/imx_keypad.c         |   4 +-
 drivers/input/keyboard/ipaq-micro-keys.c    |   2 +-
 drivers/input/keyboard/lpc32xx-keys.c       |   4 +-
 drivers/input/keyboard/pmic8xxx-keypad.c    |   4 +-
 drivers/input/keyboard/pxa27x_keypad.c      |   2 +-
 drivers/input/keyboard/samsung-keypad.c     |   4 +-
 drivers/input/keyboard/spear-keyboard.c     |   8 +-
 drivers/input/keyboard/st-keyscan.c         |   4 +-
 drivers/input/keyboard/tegra-kbc.c          |   4 +-
 drivers/input/misc/drv260x.c                |   4 +-
 drivers/input/misc/drv2665.c                |   4 +-
 drivers/input/misc/drv2667.c                |   4 +-
 drivers/input/misc/gp2ap002a00f.c           |   4 +-
 drivers/input/misc/kxtj9.c                  |   4 +-
 drivers/input/misc/sirfsoc-onkey.c          |   2 +-
 drivers/input/mouse/navpoint.c              |   4 +-
 drivers/input/touchscreen/ad7879.c          |   6 +-
 drivers/input/touchscreen/atmel_mxt_ts.c    |   4 +-
 drivers/input/touchscreen/auo-pixcir-ts.c   |   8 +-
 drivers/input/touchscreen/bu21029_ts.c      |   4 +-
 drivers/input/touchscreen/chipone_icn8318.c |   4 +-
 drivers/input/touchscreen/cyttsp_core.c     |   4 +-
 drivers/input/touchscreen/eeti_ts.c         |   4 +-
 drivers/input/touchscreen/ektf2127.c        |   4 +-
 drivers/input/touchscreen/imx6ul_tsc.c      |   4 +-
 drivers/input/touchscreen/ipaq-micro-ts.c   |   2 +-
 drivers/input/touchscreen/iqs5xx.c          |   4 +-
 drivers/input/touchscreen/lpc32xx_ts.c      |   4 +-
 drivers/input/touchscreen/melfas_mip4.c     |   4 +-
 drivers/input/touchscreen/mms114.c          |   6 +-
 drivers/input/touchscreen/pixcir_i2c_ts.c   |   8 +-
 drivers/input/touchscreen/ucb1400_ts.c      |   4 +-
 drivers/input/touchscreen/wm97xx-core.c     |  14 ++-
 drivers/input/touchscreen/zforce_ts.c       |   8 +-
 drivers/platform/x86/thinkpad_acpi.c        |   4 +-
 include/linux/input.h                       |  14 ++-
 42 files changed, 230 insertions(+), 95 deletions(-)


base-commit: 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162

Comments

Pavel Machek June 7, 2020, 8:24 p.m. UTC | #1 
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
Dmitry Torokhov June 8, 2020, 5:37 a.m. UTC | #2 
On Sun, Jun 07, 2020 at 10:24:14PM +0200, Pavel Machek wrote:
> 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...

I do not think you read the entirety of this patch series...

Thanks.
Andrzej Pietrasiewicz June 8, 2020, 9:28 a.m. UTC | #3 
Hi Pavel,

W dniu 08.06.2020 o 07:37, Dmitry Torokhov pisze:
> On Sun, Jun 07, 2020 at 10:24:14PM +0200, Pavel Machek wrote:
>> 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...
> 
> I do not think you read the entirety of this patch series...
> 

Yeah, kindly read the whole thread. Long story short: Inhibiting _is_ about
ignoring events from inhibited devices. Obviously we can do better than
just that. Indeed, the open() and close() callbacks (which are called at
uninhibiting/inhibiting) mean "start providing events" and "stop providing
events", respectively. How that translates into driver operation is highly
driver-specific and cannot be handled at the input subsystem level, but it
is the place where power savings can be realized: whenever the driver knows
that nobody wants events from it it can do whatever it considers appropriate,
including transitioning the device into low power mode, for example using
PM runtime.

Regards,

Andrzej