---

yaml
---
r: 3705
b: refs/heads/master
c: e07fefa
h: refs/heads/master
i:
  3703: d523e59
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 486e2df6ce213d0c776befdf3fe5ffc61dd61688
+refs/heads/master: e07fefa6b212f43c40fdbc1a62de690d91a4b617

trunk/drivers/usb/host/uhci-hcd.c

@@ -495,24 +495,24 @@ static int uhci_reset(struct usb_hcd *hcd)
 
 	/* The UHCI spec says devices must have 2 ports, and goes on to say
 	 * they may have more but gives no way to determine how many there
-	 * are.  However, according to the UHCI spec, Bit 7 of the port
+	 * are.  However according to the UHCI spec, Bit 7 of the port
 	 * status and control register is always set to 1.  So we try to
-	 * use this to our advantage.
+	 * use this to our advantage.  Another common failure mode when
+	 * a nonexistent register is addressed is to return all ones, so
+	 * we test for that also.
 	 */
 	for (port = 0; port < (io_size - USBPORTSC1) / 2; port++) {
 		unsigned int portstatus;
 
 		portstatus = inw(uhci->io_addr + USBPORTSC1 + (port * 2));
-		if (!(portstatus & 0x0080))
+		if (!(portstatus & 0x0080) || portstatus == 0xffff)
 			break;
 	}
 	if (debug)
 		dev_info(uhci_dev(uhci), "detected %d ports\n", port);
 
-	/* Anything less than 2 or greater than 7 is weird,
-	 * so we'll ignore it.
-	 */
-	if (port < 2 || port > UHCI_RH_MAXCHILD) {
+	/* Anything greater than 7 is weird so we'll ignore it. */
+	if (port > UHCI_RH_MAXCHILD) {
 		dev_info(uhci_dev(uhci), "port count misdetected? "
 				"forcing to 2 ports\n");
 		port = 2;