Re: [PATCH v3 2/3] usb: xhci: implement device_suspend/device_resume entries

[Lu, Baolu]

On 05/08/2015 04:47 AM, Greg Kroah-Hartman wrote:
> On Thu, May 07, 2015 at 10:18:15AM +0800, 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@xxxxxxxxxxxxxxx>
> > ---
> >   drivers/usb/host/xhci-hub.c |  2 +-
> >   drivers/usb/host/xhci.c     | 40 ++++++++++++++++++++++++++++++++++++++++
> >   drivers/usb/host/xhci.h     | 11 +++++++++++
> >   3 files changed, 52 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
> > index 0827d7c..a83e82e 100644
> > --- a/drivers/usb/host/xhci-hub.c
> > +++ b/drivers/usb/host/xhci-hub.c
> > @@ -266,7 +266,7 @@ int xhci_find_slot_id_by_port(struct usb_hcd *hcd, struct xhci_hcd *xhci,
> >    * to complete.
> >    * suspend will set to 1, if suspend bit need to set in command.
> >    */
> > -static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
> > +int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
> >   {
> >   	struct xhci_virt_device *virt_dev;
> >   	struct xhci_command *cmd;
> > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> > index ec8ac16..6b61833 100644
> > --- a/drivers/usb/host/xhci.c
> > +++ b/drivers/usb/host/xhci.c
> > @@ -4680,6 +4680,40 @@ int xhci_disable_usb3_lpm_timeout(struct usb_hcd *hcd,
> >   		return ret;
> >   	return 0;
> >   }
> > +
> > +/*
> > + * xHCI compatible host controller driver expects to be notified prior to
> > + * selectively suspending a device. xHCI hcd could optimize the endpoint
> > + * cache for power saving purpose. Refer to 4.15.1.1 of xHCI 1.1.
> > + */
> > +void xhci_device_suspend(struct usb_hcd *hcd,
> > +			struct usb_device *udev, pm_message_t msg)
> You never use the 'msg' field, so please remove it from the callback.

'msg' could be used in another patch to determine the pm event types:
auto-suspend or system suspend. I didn't bring up that patch together
with this patch series because 1) that's part of xhci 1.1 features, and
2) it's still not tested yet.

> > +{
> > +	struct xhci_hcd	*xhci;
> > +
> > +	xhci = hcd_to_xhci(hcd);
> > +	if (!xhci || !xhci->devs[udev->slot_id])
> > +		return;
> > +
> > +	xhci_stop_device(xhci, udev->slot_id, 1);
> > +}
> > +
> > +/*
> > + * xHCI compatible host controller driver expects to be notified after a
> > + * USB device is resumed. xHCI hcd could optimize the endpoint cache
> > + * to reduce the latency. Refer to 4.15.1.1 of xHCI 1.1.
> > + */
> > +void xhci_device_resume(struct usb_hcd *hcd,
> > +			struct usb_device *udev, pm_message_t msg)
> Same here.

I will remove 'msg' field in this call back. I don't see any cases where
msg could be used.

Thank you,
Baolu

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