USB: add new routine for checking port-resume type

This patch (as1070) creates a new subroutine to check whether a device
can be resumed.  This code is needed even when CONFIG_USB_SUSPEND
isn't set, because devices do suspend themselves when the root hub
(and hence the entire bus) is suspended, and power sessions can get
lost during a system sleep even without individual port suspends.

The patch also fixes a loose end in USB-Persist reset-resume handling.
When a low- or full-speed device is attached to an EHCI's companion
controller, the port handoff during resume will cause the companion
port's connect-status-change feature to be set.  If that flag isn't
cleared, the port-reset code will think it indicates that the device
has been unplugged and the reset-resume will fail.

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

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 2a5c283..d14da21 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1821,6 +1821,45 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
 
 #ifdef CONFIG_PM
 
+#define MASK_BITS      (USB_PORT_STAT_POWER | USB_PORT_STAT_CONNECTION | \
+                               USB_PORT_STAT_SUSPEND)
+#define WANT_BITS      (USB_PORT_STAT_POWER | USB_PORT_STAT_CONNECTION)
+
+/* Determine whether the device on a port is ready for a normal resume,
+ * is ready for a reset-resume, or should be disconnected.
+ */
+static int check_port_resume_type(struct usb_device *udev,
+               struct usb_hub *hub, int port1,
+               int status, unsigned portchange, unsigned portstatus)
+{
+       /* Is the device still present? */
+       if (status || (portstatus & MASK_BITS) != WANT_BITS) {
+               if (status >= 0)
+                       status = -ENODEV;
+       }
+
+       /* Can't do a normal resume if the port isn't enabled */
+       else if (!(portstatus & USB_PORT_STAT_ENABLE) && !udev->reset_resume)
+               status = -ENODEV;
+
+       if (status) {
+               dev_dbg(hub->intfdev,
+                               "port %d status %04x.%04x after resume, %d\n",
+                               port1, portchange, portstatus, status);
+       } else if (udev->reset_resume) {
+
+               /* Late port handoff can set status-change bits */
+               if (portchange & USB_PORT_STAT_C_CONNECTION)
+                       clear_port_feature(hub->hdev, port1,
+                                       USB_PORT_FEAT_C_CONNECTION);
+               if (portchange & USB_PORT_STAT_C_ENABLE)
+                       clear_port_feature(hub->hdev, port1,
+                                       USB_PORT_FEAT_C_ENABLE);
+       }
+
+       return status;
+}
+
 #ifdef CONFIG_USB_SUSPEND
 
 /*
@@ -2025,7 +2064,6 @@ int usb_port_resume(struct usb_device *udev)
        int             port1 = udev->portnum;
        int             status;
        u16             portchange, portstatus;
-       unsigned        mask_flags, want_flags;
 
        /* Skip the initial Clear-Suspend step for a remote wakeup */
        status = hub_port_status(hub, port1, &portstatus, &portchange);
@@ -2054,35 +2092,23 @@ int usb_port_resume(struct usb_device *udev)
                 */
                status = hub_port_status(hub, port1, &portstatus, &portchange);
 
- SuspendCleared:
-               if (udev->reset_resume)
-                       want_flags = USB_PORT_STAT_POWER
-                                       | USB_PORT_STAT_CONNECTION;
-               else
-                       want_flags = USB_PORT_STAT_POWER
-                                       | USB_PORT_STAT_CONNECTION
-                                       | USB_PORT_STAT_ENABLE;
-               mask_flags = want_flags | USB_PORT_STAT_SUSPEND;
+               /* TRSMRCY = 10 msec */
+               msleep(10);
+       }
 
-               if (status < 0 || (portstatus & mask_flags) != want_flags) {
-                       dev_dbg(hub->intfdev,
-                               "port %d status %04x.%04x after resume, %d\n",
-                               port1, portchange, portstatus, status);
-                       if (status >= 0)
-                               status = -ENODEV;
-               } else {
-                       if (portchange & USB_PORT_STAT_C_SUSPEND)
-                               clear_port_feature(hub->hdev, port1,
-                                               USB_PORT_FEAT_C_SUSPEND);
-                       /* TRSMRCY = 10 msec */
-                       msleep(10);
-               }
+ SuspendCleared:
+       if (status == 0) {
+               if (portchange & USB_PORT_STAT_C_SUSPEND)
+                       clear_port_feature(hub->hdev, port1,
+                                       USB_PORT_FEAT_C_SUSPEND);
        }
 
        clear_bit(port1, hub->busy_bits);
        if (!hub->hdev->parent && !hub->busy_bits[0])
                usb_enable_root_hub_irq(hub->hdev->bus);
 
+       status = check_port_resume_type(udev,
+                       hub, port1, status, portchange, portstatus);
        if (status == 0)
                status = finish_port_resume(udev);
        if (status < 0) {
@@ -2115,12 +2141,23 @@ int usb_port_suspend(struct usb_device *udev)
        return 0;
 }
 
+/* However we may need to do a reset-resume */
+
 int usb_port_resume(struct usb_device *udev)
 {
-       int status = 0;
+       struct usb_hub  *hub = hdev_to_hub(udev->parent);
+       int             port1 = udev->portnum;
+       int             status;
+       u16             portchange, portstatus;
 
-       /* However we may need to do a reset-resume */
-       if (udev->reset_resume) {
+       status = hub_port_status(hub, port1, &portstatus, &portchange);
+       status = check_port_resume_type(udev,
+                       hub, port1, status, portchange, portstatus);
+
+       if (status) {
+               dev_dbg(&udev->dev, "can't resume, status %d\n", status);
+               hub_port_logical_disconnect(hub, port1);
+       } else if (udev->reset_resume) {
                dev_dbg(&udev->dev, "reset-resume\n");
                status = usb_reset_device(udev);
        }