linux-kernel - Re: [PATCH v3 4/4] Input: Don't send fake button presses to wake system

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Message-ID: <363c2b92-4bfc-4537-9fca-025eef09526f@kernel.org>
Date: Thu, 26 Jun 2025 12:53:02 -0500
From: Mario Limonciello <superm1@...nel.org>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: Hans de Goede <hansg@...nel.org>, Mika Westerberg <westeri@...nel.org>,
 Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
 Linus Walleij <linus.walleij@...aro.org>, Bartosz Golaszewski
 <brgl@...ev.pl>, "open list:GPIO ACPI SUPPORT" <linux-gpio@...r.kernel.org>,
 "open list:GPIO ACPI SUPPORT" <linux-acpi@...r.kernel.org>,
 open list <linux-kernel@...r.kernel.org>,
 "open list:INPUT (KEYBOARD, MOUSE, JOYSTICK, TOUCHSCREEN)..."
 <linux-input@...r.kernel.org>, Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v3 4/4] Input: Don't send fake button presses to wake
 system



On 6/26/25 12:44 PM, Dmitry Torokhov wrote:
> Hi Mario,
> 
> On Thu, Jun 26, 2025 at 06:33:08AM -0500, Mario Limonciello wrote:
>>
>>
>> On 6/26/25 3:35 AM, Hans de Goede wrote:
>>> Hi Mario,
>>>
>>> On 25-Jun-25 23:58, Mario Limonciello wrote:
>>>> From: Mario Limonciello <mario.limonciello@....com>
>>>>
>>>> Sending an input event to wake a system does wake it, but userspace picks
>>>> up the keypress and processes it.  This isn't the intended behavior as it
>>>> causes a suspended system to wake up and then potentially turn off if
>>>> userspace is configured to turn off on power button presses.
>>>>
>>>> Instead send a PM wakeup event for the PM core to handle waking the system.
>>>>
>>>> Cc: Hans de Goede <hansg@...nel.org>
>>>> Fixes: 0f107573da417 ("Input: gpio_keys - handle the missing key press event in resume phase")
>>>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>>>> ---
>>>>    drivers/input/keyboard/gpio_keys.c | 7 +------
>>>>    1 file changed, 1 insertion(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
>>>> index 773aa5294d269..4c6876b099c43 100644
>>>> --- a/drivers/input/keyboard/gpio_keys.c
>>>> +++ b/drivers/input/keyboard/gpio_keys.c
>>>> @@ -420,12 +420,7 @@ static irqreturn_t gpio_keys_gpio_isr(int irq, void *dev_id)
>>>>    		pm_stay_awake(bdata->input->dev.parent);
>>>>    		if (bdata->suspended  &&
>>>>    		    (button->type == 0 || button->type == EV_KEY)) {
>>>> -			/*
>>>> -			 * Simulate wakeup key press in case the key has
>>>> -			 * already released by the time we got interrupt
>>>> -			 * handler to run.
>>>> -			 */
>>>> -			input_report_key(bdata->input, button->code, 1);
>>>> +			pm_wakeup_event(bdata->input->dev.parent, 0);
> 
> There is already pm_stay_awake() above.

But that doesn't help with the fact that userspace gets KEY_POWER from 
this and reacts to it.

> 
>>>>    		}
>>>>    	}
>>>
>>> Hmm, we have the same problem on many Bay Trail / Cherry Trail
>>> windows 8 / win10 tablets, so  this has been discussed before and e.g.
>>> Android userspace actually needs the button-press (evdev) event to not
>>> immediately go back to sleep, so a similar patch has been nacked in
>>> the past.
>>>
>>> At least for GNOME this has been fixed in userspace by ignoring
>>> power-button events the first few seconds after a resume from suspend.
>>>
>>
>> The default behavior for logind is:
>>
>> HandlePowerKey=poweroff
>>
>> Can you share more about what version of GNOME has a workaround?
>> This was actually GNOME (on Ubuntu 24.04) that I found this issue.
>>
>> Nonetheless if this is dependent on an Android userspace problem could we
>> perhaps conditionalize it on CONFIG_ANDROID_BINDER_DEVICES?
> 
> No it is not only Android, other userspace may want to distinguish
> between normal and "dark" resume based on keyboard or other user
> activity.
> 
> Thanks.
> 
In this specific case does the key passed up to satisfy this userspace 
requirement and keep it awake need to specifically be a fabricated 
KEY_POWER?

Or could we find a key that doesn't require some userspace to ignore 
KEY_POWER?

Maybe something like KEY_RESERVED, KEY_FN, or KEY_POWER2?