Re: [PATCH v2 2/3] usb: xhci: implement device_suspend/device_resume entries

["Lu, Baolu" <baolu.lu@linux.intel.com>]

On 05/06/2015 10:30 PM, Alan Stern wrote:
> On Wed, 6 May 2015, Lu Baolu wrote:
>
>> This patch implements device_suspend/device_resume entries for xHC driver.
>> device_suspend will be called when a USB device is about to suspend. It
>> will issue a stop endpoint command for each endpoint in this device. The
>> Suspend(SP) bit in the command TRB will set which will give xHC a hint
>> about the suspend. device_resume will be called when a USB device is just
>> resumed. It will ring doorbells of all endpoint unconditionally. XHC may
>> use these suspend/resume hints to optimize its operation.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ...
>
>>   #else /* CONFIG_PM */
>>   
>>   int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
>> @@ -4704,6 +4728,16 @@ int xhci_disable_usb3_lpm_timeout(struct usb_hcd *hcd,
>>   {
>>   	return 0;
>>   }
>> +
>> +void xhci_device_suspend(struct usb_hcd *hcd,
>> +			struct usb_device *udev, pm_message_t msg)
>> +{
>> +}
>> +
>> +void xhci_device_resume(struct usb_hcd *hcd,
>> +			struct usb_device *udev, pm_message_t msg)
>> +{
>> +}
> You don't need to have empty functions.  Just do this:
>
> #define xhci_device_suspend	NULL
> #define xhci_device_resume	NULL
>
> in the appropriate place, when CONFIG_PM is not enabled.

Yes, I agree. I will change it.

>
> Alan Stern

Thank you,
Baolu

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