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...@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.
Alan Stern
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