linux-kernel - Re: [PATCH 2/3] Revert "Input: hyperv-keyboard

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Message-ID: <20241017134438.GA14386@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
Date: Thu, 17 Oct 2024 06:44:38 -0700
From: Erni Sri Satya Vennela <ernis@...ux.microsoft.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: "Srivatsa S. Bhat" <srivatsa@...il.mit.edu>, kys@...rosoft.com,
	haiyangz@...rosoft.com, wei.liu@...nel.org, decui@...rosoft.com,
	jikos@...nel.org, bentiss@...nel.org, linux-hyperv@...r.kernel.org,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	ernis@...rosoft.com, rafael@...nel.org, pavel@....cz,
	lenb@...nel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/3] Revert "Input: hyperv-keyboard - register as a
 wakeup source"

On Fri, Oct 04, 2024 at 01:14:10AM -0700, Dmitry Torokhov wrote:
> On Tue, Sep 24, 2024 at 03:28:51AM +0000, Srivatsa S. Bhat wrote:
> > [+linux-pm, Rafael, Len, Pavel]
> > 
> > On Thu, Sep 12, 2024 at 02:27:49PM -0700, Erni Sri Satya Vennela wrote:
> > > This reverts commit 62238f3aadc9bc56da70100e19ec61b9f8d72a5f.
> > > 
> > > Remove keyboard as wakeup source since Suspend-to-Idle feature
> > > is disabled.
> > > 
> > > Signed-off-by: Erni Sri Satya Vennela <ernis@...ux.microsoft.com>
> > > ---
> > >  drivers/input/serio/hyperv-keyboard.c | 12 ------------
> > >  1 file changed, 12 deletions(-)
> > > 
> > > diff --git a/drivers/input/serio/hyperv-keyboard.c b/drivers/input/serio/hyperv-keyboard.c
> > > index 31d9dacd2fd1..b42c546636bf 100644
> > > --- a/drivers/input/serio/hyperv-keyboard.c
> > > +++ b/drivers/input/serio/hyperv-keyboard.c
> > > @@ -162,15 +162,6 @@ static void hv_kbd_on_receive(struct hv_device *hv_dev,
> > >  			serio_interrupt(kbd_dev->hv_serio, scan_code, 0);
> > >  		}
> > >  		spin_unlock_irqrestore(&kbd_dev->lock, flags);
> > > -
> > > -		/*
> > > -		 * Only trigger a wakeup on key down, otherwise
> > > -		 * "echo freeze > /sys/power/state" can't really enter the
> > > -		 * state because the Enter-UP can trigger a wakeup at once.
> > > -		 */
> > > -		if (!(info & IS_BREAK))
> > > -			pm_wakeup_hard_event(&hv_dev->device);
> > > -
> > >  		break;
> > >  
> > >  	default:
> > > @@ -356,9 +347,6 @@ static int hv_kbd_probe(struct hv_device *hv_dev,
> > >  		goto err_close_vmbus;
> > >  
> > >  	serio_register_port(kbd_dev->hv_serio);
> > > -
> > > -	device_init_wakeup(&hv_dev->device, true);
> 
> If you do not want the keyboard to be a wakeup source by default maybe
> change this to:
> 
> 	device_set_wakeup_capable(&hv_dev->device, true);
> 
> and leave the rest of the driver alone?
> 
> Same for the HID change.
> 
> Thanks.
>
device_set_wakeup_capable() sets the @dev's power.can_wakeup flag and
adds wakeup-related attributes in sysfs.

Could you please help me understand why explicitly calling this function 
can be helpful in our use case?

> -- 
> Dmitry