USB: simplify hub_restart() logic

This patch (as1081) straightens out the logic of the hub_restart()
routine.  Each port of the hub is scanned and the driver makes sure
that ports which are supposed to be disabled really _are_ disabled.
Any ports with a significant change in status are flagged in
hub->change_bits, so that khubd can focus on them without the need to
scan all the ports a second time -- which means the hub->activating
flag is no longer needed.

Also, it is now recognized explicitly that the only reason for
resuming a port which was not suspended is to carry out a reset-resume
operation, which happens only in a non-CONFIG_USB_SUSPEND setting.

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

2 files changed, 54 insertions, 67 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index d0b37d776afe..bf1585b203ca 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -805,8 +805,6 @@ static int usb_resume_device(struct usb_device *udev)
 
         if (udev->state == USB_STATE_NOTATTACHED)
                 goto done;
-        if (udev->state != USB_STATE_SUSPENDED && !udev->reset_resume)
-                goto done;
 
         /* Can't resume it if it doesn't have a driver. */
         if (udev->dev.driver == NULL) {
@@ -1173,11 +1171,8 @@ static int usb_resume_both(struct usb_device *udev)
                          * then we're stuck. */
                         status = usb_resume_device(udev);
                 }
-        } else {
-
-                /* Needed for reset-resume */
+        } else if (udev->reset_resume)
                 status = usb_resume_device(udev);
-        }
 
         if (status == 0 && udev->actconfig) {
                 for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 976da1c4919b..054a76dc5d5b 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -72,7 +72,6 @@ struct usb_hub {
 
         unsigned                limited_power:1;
         unsigned                quiescing:1;
-        unsigned                activating:1;
         unsigned                disconnected:1;
 
         unsigned                has_indicators:1;
@@ -539,7 +538,6 @@ static void hub_quiesce(struct usb_hub *hub)
 {
         /* (nonblocking) khubd and related activity won't re-trigger */
         hub->quiescing = 1;
-        hub->activating = 0;
 
         /* (blocking) stop khubd and related activity */
         usb_kill_urb(hub->urb);
@@ -554,7 +552,6 @@ static void hub_activate(struct usb_hub *hub)
         int     status;
 
         hub->quiescing = 0;
-        hub->activating = 1;
 
         status = usb_submit_urb(hub->urb, GFP_NOIO);
         if (status < 0)
@@ -638,81 +635,83 @@ static void hub_stop(struct usb_hub *hub)
         hub_quiesce(hub);
 }
 
-#define HUB_RESET               1
-#define HUB_RESUME              2
-#define HUB_RESET_RESUME        3
-
-#ifdef CONFIG_PM
+enum hub_activation_type {
+        HUB_INIT, HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME
+};
 
-static void hub_restart(struct usb_hub *hub, int type)
+static void hub_restart(struct usb_hub *hub, enum hub_activation_type type)
 {
         struct usb_device *hdev = hub->hdev;
         int port1;
 
-        /* Check each of the children to see if they require
-         * USB-PERSIST handling or disconnection.  Also check
-         * each unoccupied port to make sure it is still disabled.
+        /* Check each port and set hub->change_bits to let khubd know
+         * which ports need attention.
          */
         for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
                 struct usb_device *udev = hdev->children[port1-1];
-                int status = 0;
+                int status;
                 u16 portstatus, portchange;
 
-                if (!udev || udev->state == USB_STATE_NOTATTACHED) {
-                        if (type != HUB_RESET) {
-                                status = hub_port_status(hub, port1,
-                                                &portstatus, &portchange);
-                                if (status == 0 && (portstatus &
-                                                USB_PORT_STAT_ENABLE))
-                                        clear_port_feature(hdev, port1,
-                                                        USB_PORT_FEAT_ENABLE);
-                        }
-                        continue;
+                portstatus = portchange = 0;
+                status = hub_port_status(hub, port1, &portstatus, &portchange);
+                if (udev || (portstatus & USB_PORT_STAT_CONNECTION))
+                        dev_dbg(hub->intfdev,
+                                        "port %d: status %04x change %04x\n",
+                                        port1, portstatus, portchange);
+
+                /* After anything other than HUB_RESUME (i.e., initialization
+                 * or any sort of reset), every port should be disabled.
+                 * Unconnected ports should likewise be disabled (paranoia),
+                 * and so should ports for which we have no usb_device.
+                 */
+                if ((portstatus & USB_PORT_STAT_ENABLE) && (
+                                type != HUB_RESUME ||
+                                !(portstatus & USB_PORT_STAT_CONNECTION) ||
+                                !udev ||
+                                udev->state == USB_STATE_NOTATTACHED)) {
+                        clear_port_feature(hdev, port1, USB_PORT_FEAT_ENABLE);
+                        portstatus &= ~USB_PORT_STAT_ENABLE;
                 }
 
-                /* Was the power session lost while we were suspended? */
-                switch (type) {
-                case HUB_RESET_RESUME:
-                        portstatus = 0;
-                        portchange = USB_PORT_STAT_C_CONNECTION;
-                        break;
-
-                case HUB_RESET:
-                case HUB_RESUME:
-                        status = hub_port_status(hub, port1,
-                                        &portstatus, &portchange);
-                        break;
-                }
+                if (!udev || udev->state == USB_STATE_NOTATTACHED) {
+                        /* Tell khubd to disconnect the device or
+                         * check for a new connection
+                         */
+                        if (udev || (portstatus & USB_PORT_STAT_CONNECTION))
+                                set_bit(port1, hub->change_bits);
+
+                } else if (portstatus & USB_PORT_STAT_ENABLE) {
+                        /* The power session apparently survived the resume.
+                         * If there was an overcurrent or suspend change
+                         * (i.e., remote wakeup request), have khubd
+                         * take care of it.
+                         */
+                        if (portchange)
+                                set_bit(port1, hub->change_bits);
 
-                /* For "USB_PERSIST"-enabled children we must
-                 * mark the child device for reset-resume and
-                 * turn off the various status changes to prevent
-                 * khubd from disconnecting it later.
-                 */
-                if (udev->persist_enabled && status == 0 &&
-                                !(portstatus & USB_PORT_STAT_ENABLE)) {
+                } else if (udev->persist_enabled) {
+                        /* Turn off the status changes to prevent khubd
+                         * from disconnecting the device.
+                         */
                         if (portchange & USB_PORT_STAT_C_ENABLE)
                                 clear_port_feature(hub->hdev, port1,
                                                 USB_PORT_FEAT_C_ENABLE);
                         if (portchange & USB_PORT_STAT_C_CONNECTION)
                                 clear_port_feature(hub->hdev, port1,
                                                 USB_PORT_FEAT_C_CONNECTION);
+#ifdef CONFIG_PM
                         udev->reset_resume = 1;
+#endif
+                } else {
+                        /* The power session is gone; tell khubd */
+                        usb_set_device_state(udev, USB_STATE_NOTATTACHED);
+                        set_bit(port1, hub->change_bits);
                 }
-
-                /* Otherwise for a reset_resume we must disconnect the child,
-                 * but as we may not lock the child device here
-                 * we have to do a "logical" disconnect.
-                 */
-                else if (type == HUB_RESET_RESUME)
-                        hub_port_logical_disconnect(hub, port1);
         }
 
         hub_activate(hub);
 }
 
-#endif  /* CONFIG_PM */
-
 /* caller has locked the hub device */
 static int hub_pre_reset(struct usb_interface *intf)
 {
@@ -728,7 +727,7 @@ static int hub_post_reset(struct usb_interface *intf)
         struct usb_hub *hub = usb_get_intfdata(intf);
 
         hub_power_on(hub);
-        hub_activate(hub);
+        hub_restart(hub, HUB_POST_RESET);
         return 0;
 }
 
@@ -2903,7 +2902,7 @@ static void hub_events(void)
                                 continue;
                         connect_change = test_bit(i, hub->change_bits);
                         if (!test_and_clear_bit(i, hub->event_bits) &&
-                                        !connect_change && !hub->activating)
+                                        !connect_change)
                                 continue;
 
                         ret = hub_port_status(hub, i,
@@ -2911,11 +2910,6 @@ static void hub_events(void)
                         if (ret < 0)
                                 continue;
 
-                        if (hub->activating && !hdev->children[i-1] &&
-                                        (portstatus &
-                                                USB_PORT_STAT_CONNECTION))
-                                connect_change = 1;
-
                         if (portchange & USB_PORT_STAT_C_CONNECTION) {
                                 clear_port_feature(hdev, i,
                                         USB_PORT_FEAT_C_CONNECTION);
@@ -3011,8 +3005,6 @@ static void hub_events(void)
                         }
                 }
 
-                hub->activating = 0;
-
                 /* If this is a root hub, tell the HCD it's okay to
                  * re-enable port-change interrupts now. */
                 if (!hdev->parent && !hub->busy_bits[0])