Hi Greg, > > > > > + > > > > > + if (!ret) { > > > > > + struct usb_device *hdev = hub->hdev; > > > > > + > > > > > + if (hdev && !hdev->parent) { > > > > > > > > Why the check for no parent? Please document that here in a > comment. > > > > > > I will add a comment : > > > /* Only notify roothub. That is, when hdev->parent is empty. */ > > > > Also document this that this will only happen for root hub status > > changes, that's not obvious in the callback name or documentation or > anywhere else here. > > All usb phy notifications (connection, disconnection) are only for roothub. > So I don't special to doc this. I will add the comment: /* * Applies to roothub only. That is, when hdev->parent is * empty. Only the roothub will be notified of port state * changes, since the USB PHY only cares about changes at * the next level. */ Thanks, Stanley