Message-ID: <9bf4463c-6541-a6cb-9bbc-6d070118509a@allwinnertech.com>
Date:   Thu, 23 Feb 2023 19:18:12 +0800
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Subject: Re: [PATCH] HID: usbhid: enable remote wakeup for mice
Content-Language: en-US
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     jikos@kernel.org, benjamin.tissoires@redhat.com,
        linux-usb@vger.kernel.org, linux-input@vger.kernel.org,
        linux-kernel@vger.kernel.org, mario.limonciello@amd.com,
        richard.gong@amd.com
References: <20230222013944.31095-1-michael@allwinnertech.com>
 <Y/WwXBF37hoZBbQa@kroah.com>
From:   Michael Wu <michael@allwinnertech.com>
In-Reply-To: <Y/WwXBF37hoZBbQa@kroah.com>
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Dear Greg,

On 2/22/2023 2:04 PM, Greg KH wrote:
> On Wed, Feb 22, 2023 at 09:39:44AM +0800, Michael Wu wrote:
>> This patch fixes a problem that USB mouse can't wake up the device that
>> enters standby.
> 
> This not a problem, it is that way by design.

I got it, maybe it's a little problem to say that.

> 
>> At present, the kernel only checks whether certain USB manufacturers
>> support wake-up, which will easily cause inconvenience to the
>> development work of other manufacturers and add unnecessary work to the
>> maintenance of kernel.
>>
>> The USB protocol supports judging whether a usb supports the wake-up
>> function, so it should be more reasonable to add a wake-up source by
>> directly checking the settings from the USB protocol.
> 
> But you do not do that in this patch, why not?

I just want to explain the background of my patch, to prove we could use 
a similar way to avoid such a "disturbing" situation.
To reduce the influence, my patch enables remote wakeup for USB mouse 
devices refer to what keyboard do.

> 
>> There was a similar issue on the keyboard before, which was fixed by
>> this patch (3d61510f4eca), but now the problem happened on the mouse.
>> This patch uses a similar idea to fix this problem.
>>
>> Signed-off-by: Michael Wu <michael@allwinnertech.com>
>> ---
>>   drivers/hid/usbhid/hid-core.c | 8 ++++++++
>>   drivers/hid/usbhid/usbmouse.c | 1 +
>>   2 files changed, 9 insertions(+)
>>
>> diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
>> index be4c731aaa65..d3a6755cca09 100644
>> --- a/drivers/hid/usbhid/hid-core.c
>> +++ b/drivers/hid/usbhid/hid-core.c
>> @@ -1189,6 +1189,14 @@ static int usbhid_start(struct hid_device *hid)
>>   		device_set_wakeup_enable(&dev->dev, 1);
>>   	}
>>   
>> +	/**
>> +	 * NOTE: enable remote wakeup by default for all mouse devices
>> +	 * supporting the boot protocol.
>> +	 */
>> +	if (interface->desc.bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT &&
>> +	    interface->desc.bInterfaceProtocol == USB_INTERFACE_PROTOCOL_MOUSE)
>> +		device_set_wakeup_enable(&dev->dev, 1);
> 
> Sorry, but we can not take this unless it is proven that this will work
> properly for all of these devices.  Other operating systems do not do
> this last I checked, so there will be problems.

As Mario Limonciello says, they has confirmed that the Microsoft Windows 
does set a similar policy as well. Can we talk about more in this topic: 
why does Linux not support it?
Of course, if you have other great idea, I will appreciate that if we 
can have some further discussion.

> 
> thanks,
> 
> greg k-h

-- 
Regards,
Michael Wu