On Wed, May 08, 2019 at 11:28:05AM -0600, shuah wrote: > On 5/7/19 9:49 AM, Suwan Kim wrote: > > Hi Shuah, > > > > On Mon, May 06, 2019 at 09:13:02AM -0600, shuah wrote: > > > On 5/6/19 6:55 AM, Suwan Kim wrote: > > > > When hcd suspends execution, hcd_bus_suspend() calls vhci_bus_suspend() > > > > which sets hcd->state as HC_STATE_SUSPENDED. But after calling > > > > vhci_bus_suspend(), hcd_bus_suspend() also sets hcd->state as > > > > HC_STATE_SUSPENDED. > > > > So, setting hcd->state in vhci_hcd_suspend() is unnecessary. > > > > > > > > Signed-off-by: Suwan Kim <suwan.kim027@xxxxxxxxx> > > > > --- > > > > drivers/usb/usbip/vhci_hcd.c | 4 ---- > > > > 1 file changed, 4 deletions(-) > > > > > > > > diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c > > > > index 667d9c0ec905..e6f378d00fb6 100644 > > > > --- a/drivers/usb/usbip/vhci_hcd.c > > > > +++ b/drivers/usb/usbip/vhci_hcd.c > > > > @@ -1238,10 +1238,6 @@ static int vhci_bus_suspend(struct usb_hcd *hcd) > > > > dev_dbg(&hcd->self.root_hub->dev, "%s\n", __func__); > > > > - spin_lock_irqsave(&vhci->lock, flags); > > > > - hcd->state = HC_STATE_SUSPENDED; > > > > - spin_unlock_irqrestore(&vhci->lock, flags); > > > > - > > > > return 0; > > > > } > > > > > > > > > > Tell me more about why you think this change is needed? How did you test > > > this change? > > > > I think that host controller specific functions, vhci_bus_resume() > > or vhci_bus_suspend() in the case of vhci, usually process host > > controller specific data (struct vhci_hcd) not a generic data > > (struct usb_hcd). The generic data is usually processed by generic HCD > > layer. But vhci_bus_resume() and vhci_bus_suspend() set generic data > > (hcd->state) and moreover this variable is set in generic HCD layer > > once again(hcd_bus_resume() and hcd_bus_suspend()). > > > > So, i think host controller specific functions (vhci_bus_resume() > > and vhci_bus_suspend()) don't need to set the generic data that is > > "hcd->state = HC_STATE_RUNNING or HC_STATE_SUSPEND". > > > > It depends. In this case, vhci_hcd is virtual driver and maintains > port status for devices that are remote. It checks hcd->state in > vhci_hub_status(). > > It updates the hcd->state in suspend with vhci->lock hold and checks > status from vhci_hub_status(). Removing updating hcd->state from > vhci_bus_suspend()will open a window where vhci_hub_status() might > find it wrong state. > I didn't know that and I missed. Thank you for pointing out my fault. I agree that removing updating hcd->state which is protected by vhci lock is not correct. But I still have not fully understood the relationship between vhci_bus_suspend() and vhci_hub_status() yet. I will look at it in more detail. Again, thank you for reviewing my patch. Regards Suwan Kim
