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>

diff --git a/drivers/usb/host/uhci-hub.c b/drivers/usb/host/uhci-hub.c
index bacc25c..8e4427a 100644 (file)
--- 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)