Re: Double tap to wake optionality

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi David,

On Mon, Sep 07, 2026 at 12:02:12AM +0200, David Heidelberg wrote:
> Hello!
> 
> Most of touchscreens has ability to jump into low power mode and get woken
> up by gesture (such as double tap).
> 
> I wonder about suggestion what property should drivers use to implement this
> policy where driver doesn't have to jump into low-power mode but completely
> power-off (and save battery). My thinking was something such as
> 
> /sys/class/input/inputX/gesture_to_wake
> (while gesture sounds a bit weird, it seems that TS are capable to recognize
> different patterns, not only double-tap).
> 
> 
>                     userspace
>                        │
>                        │ gesture_to_wake = 1
>                        ▼
>               touchscreen driver
>                        │
>           ┌────────────┴────────────┐
>           │                         │
>        gesture ON               gesture OFF
>           │                         │
>           ▼                         ▼
>    low-power TS mode          complete power-off
>           │
>           ▼
>      IRQ configured
>      as wake source

How is it different from the power/wakeup device attribute? Device's
suspend  routines check device_may_wakeup() and then either completely
power off controllers or configure them for wake up.

How exactly wakeup is handled - any touch, or double-tap, or something
else - is up to the controller and its firmware.

Thanks.

-- 
Dmitry