linux-kernel - Re: [PATCH 4/5] Input: xpad - restore LED state after device resume

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Date:   Mon, 6 Feb 2017 14:57:11 -0800
From:   Cameron Gutman <aicommander@...il.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     rojtberg@...il.com, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] Input: xpad - restore LED state after device resume

On 02/06/2017 02:05 PM, Dmitry Torokhov wrote:
> On Sat, Feb 04, 2017 at 04:30:01PM -0800, Cameron Gutman wrote:
>> The state of pad LEDs can be inconsistent when the system is
>> woken up after sleep. Rather than leaving the controllers blinking,
>> let's resend the last LED command to Xbox 360 pads on resume.
>>
>> Since Xbox One pads stop flashing only when reinitialized, we'll
>> send them the initialization packet so they calm down too.
>>
>> Signed-off-by: Cameron Gutman <aicommander@...il.com>
>> ---
>>  drivers/input/joystick/xpad.c | 14 +++++++++++++-
>>  1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
>> index 13f298d..1179266 100644
>> --- a/drivers/input/joystick/xpad.c
>> +++ b/drivers/input/joystick/xpad.c
>> @@ -1683,11 +1683,23 @@ static int xpad_resume(struct usb_interface *intf)
>>  		retval = xpad360w_start_input(xpad);
>>  	} else {
>>  		mutex_lock(&input->mutex);
>> -		if (input->users)
>> +		if (input->users) {
>>  			retval = xpad_start_input(xpad);
>> +		} else if (xpad->xtype == XTYPE_XBOXONE) {
>> +			/*
>> +			 * Even if there are no users, we'll send Xbox One pads
>> +			 * the startup sequence so they don't sit there and
>> +			 * blink until somebody opens the input device again.
>> +			 */
>> +			retval = xpad_start_xbox_one(xpad);
>> +		}
>>  		mutex_unlock(&input->mutex);
>>  	}
>>  
>> +	/* LED state is lost across resume, so resend the last command */
>> +	if (xpad->led)
>> +		xpad_send_led_command(xpad, xpad->led->led_cdev.brightness);
> 
> I can see that we might need to send the "start" command, but I am not
> sure that explicitly calling xpad_send_led_command() is needed: LED core
> should restore LED state upon resume, and this should happen after its
> parent (i.e. xbox device) is resumed.
> 
> Thanks.
> 

Ah, so it seems we're missing the LED_CORE_SUSPENDRESUME flag on our LED
device required for that to happen automatically. I'll just use that
instead of manually setting brightness on resume.