UHCI: fix port resume problem

This patch (as863) fixes a problem encountered sometimes when resuming
a port on a UHCI controller.  The hardware may turn off the
Resume-Detect bit before turning off the Suspend bit, leading usbcore
to think that the port is still suspended and the resume has failed.
The patch makes uhci_finish_suspend() wait until both bits are safely
off.

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

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/usb/host/uhci-hub.c b/drivers/usb/host/uhci-hub.c
index bacc25c53ba..8e4427aebb1 100644
--- a/drivers/usb/host/uhci-hub.c
+++ b/drivers/usb/host/uhci-hub.c
@@ -33,6 +33,9 @@ static __u8 root_hub_hub_des[] =
 /* status change bits:  nonzero writes will clear */
 #define RWC_BITS        (USBPORTSC_OCC | USBPORTSC_PEC | USBPORTSC_CSC)
 
+/* suspend/resume bits: port suspended or port resuming */
+#define SUSPEND_BITS    (USBPORTSC_SUSP | USBPORTSC_RD)
+
 /* A port that either is connected or has a changed-bit set will prevent
  * us from AUTO_STOPPING.
  */
@@ -96,8 +99,8 @@ static void uhci_finish_suspend(struct uhci_hcd *uhci, int port,
         int status;
         int i;
 
-        if (inw(port_addr) & (USBPORTSC_SUSP | USBPORTSC_RD)) {
-                CLR_RH_PORTSTAT(USBPORTSC_SUSP | USBPORTSC_RD);
+        if (inw(port_addr) & SUSPEND_BITS) {
+                CLR_RH_PORTSTAT(SUSPEND_BITS);
                 if (test_bit(port, &uhci->resuming_ports))
                         set_bit(port, &uhci->port_c_suspend);
 
@@ -107,7 +110,7 @@ static void uhci_finish_suspend(struct uhci_hcd *uhci, int port,
                  * Experiments show that some controllers take longer, so
                  * we'll poll for completion. */
                 for (i = 0; i < 10; ++i) {
-                        if (!(inw(port_addr) & USBPORTSC_RD))
+                        if (!(inw(port_addr) & SUSPEND_BITS))
                                 break;
                         udelay(1);
                 }
@@ -289,7 +292,7 @@ static int uhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
                         wPortStatus |= USB_PORT_STAT_CONNECTION;
                 if (status & USBPORTSC_PE) {
                         wPortStatus |= USB_PORT_STAT_ENABLE;
-                        if (status & (USBPORTSC_SUSP | USBPORTSC_RD))
+                        if (status & SUSPEND_BITS)
                                 wPortStatus |= USB_PORT_STAT_SUSPEND;
                 }
                 if (status & USBPORTSC_OC)