USB: EHCI: improve use of per-port status-change bits

This patch (as1634) simplifies some of the code associated with the
per-port change bits added in EHCI-1.1, and in particular it fixes a
bug in the logic of ehci_hub_status_data().  Even if the change bit
doesn't indicate anything happened on a particular port, we still have
to notify the core about changes to the suspend or reset status.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-hcd.c

@@ -758,7 +758,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
 	/* remote wakeup [4.3.1] */
 	if (status & STS_PCD) {
 		unsigned	i = HCS_N_PORTS (ehci->hcs_params);
-		u32		ppcd = 0;
+		u32		ppcd = ~0;
 
 		/* kick root hub later */
 		pcd_status = status;
@@ -775,7 +775,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
 			int pstatus;
 
 			/* leverage per-port change bits feature */
-			if (ehci->has_ppcd && !(ppcd & (1 << i)))
+			if (!(ppcd & (1 << i)))
 				continue;
 			pstatus = ehci_readl(ehci,
 					 &ehci->regs->port_status[i]);

drivers/usb/host/ehci-hub.c

@@ -590,7 +590,7 @@ ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
 	u32		mask;
 	int		ports, i, retval = 1;
 	unsigned long	flags;
-	u32		ppcd = 0;
+	u32		ppcd = ~0;
 
 	/* init status to no-changes */
 	buf [0] = 0;
@@ -628,9 +628,10 @@ ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
 
 	for (i = 0; i < ports; i++) {
 		/* leverage per-port change bits feature */
-		if (ehci->has_ppcd && !(ppcd & (1 << i)))
-			continue;
-		temp = ehci_readl(ehci, &ehci->regs->port_status [i]);
+		if (ppcd & (1 << i))
+			temp = ehci_readl(ehci, &ehci->regs->port_status[i]);
+		else
+			temp = 0;
 
 		/*
 		 * Return status information even for ports with OWNER set.