USB: Add autosuspend support to the hub driver

This patch (as742b) adds autosuspend/autoresume support to the USB hub
driver.  The largest aspect of the change is that we no longer need a
special flag for root hubs that want to be resumed.  Now every hub is
autoresumed whenever khubd needs to access it.

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

1 files changed, 26 insertions, 19 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index f6e692180587..55812a5ac661 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -65,7 +65,6 @@ struct usb_hub {
         unsigned                limited_power:1;
         unsigned                quiescing:1;
         unsigned                activating:1;
-        unsigned                resume_root_hub:1;
 
         unsigned                has_indicators:1;
         u8                      indicator[USB_MAXCHILDREN];
@@ -328,6 +327,9 @@ static void kick_khubd(struct usb_hub *hub)
 {
         unsigned long   flags;
 
+        /* Suppress autosuspend until khubd runs */
+        to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;
+
         spin_lock_irqsave(&hub_event_lock, flags);
         if (list_empty(&hub->event_list)) {
                 list_add_tail(&hub->event_list, &hub_event_list);
@@ -509,7 +511,6 @@ static void hub_quiesce(struct usb_hub *hub)
         /* (nonblocking) khubd and related activity won't re-trigger */
         hub->quiescing = 1;
         hub->activating = 0;
-        hub->resume_root_hub = 0;
 
         /* (blocking) stop khubd and related activity */
         usb_kill_urb(hub->urb);
@@ -525,7 +526,7 @@ static void hub_activate(struct usb_hub *hub)
 
         hub->quiescing = 0;
         hub->activating = 1;
-        hub->resume_root_hub = 0;
+
         status = usb_submit_urb(hub->urb, GFP_NOIO);
         if (status < 0)
                 dev_err(hub->intfdev, "activate --> %d\n", status);
@@ -940,6 +941,7 @@ descriptor_error:
         INIT_WORK(&hub->leds, led_work, hub);
 
         usb_set_intfdata (intf, hub);
+        intf->needs_remote_wakeup = 1;
 
         if (hdev->speed == USB_SPEED_HIGH)
                 highspeed_hubs++;
@@ -1938,6 +1940,8 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
                 }
         }
 
+        dev_dbg(&intf->dev, "%s\n", __FUNCTION__);
+
         /* "global suspend" of the downstream HC-to-USB interface */
         if (!hdev->parent) {
                 struct usb_bus  *bus = hdev->bus;
@@ -1960,10 +1964,12 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
 
 static int hub_resume(struct usb_interface *intf)
 {
-        struct usb_device       *hdev = interface_to_usbdev(intf);
         struct usb_hub          *hub = usb_get_intfdata (intf);
+        struct usb_device       *hdev = hub->hdev;
         int                     status;
 
+        dev_dbg(&intf->dev, "%s\n", __FUNCTION__);
+
         /* "global resume" of the downstream HC-to-USB interface */
         if (!hdev->parent) {
                 struct usb_bus  *bus = hdev->bus;
@@ -2002,7 +2008,6 @@ void usb_resume_root_hub(struct usb_device *hdev)
 {
         struct usb_hub *hub = hdev_to_hub(hdev);
 
-        hub->resume_root_hub = 1;
         kick_khubd(hub);
 }
 
@@ -2639,16 +2644,13 @@ static void hub_events(void)
                 intf = to_usb_interface(hub->intfdev);
                 hub_dev = &intf->dev;
 
-                i = hub->resume_root_hub;
-
-                dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x%s\n",
+                dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
                                 hdev->state, hub->descriptor
                                         ? hub->descriptor->bNbrPorts
                                         : 0,
                                 /* NOTE: expects max 15 ports... */
                                 (u16) hub->change_bits[0],
-                                (u16) hub->event_bits[0],
-                                i ? ", resume root" : "");
+                                (u16) hub->event_bits[0]);
 
                 usb_get_intf(intf);
                 spin_unlock_irq(&hub_event_lock);
@@ -2669,16 +2671,16 @@ static void hub_events(void)
                         goto loop;
                 }
 
-                /* Is this is a root hub wanting to reactivate the downstream
-                 * ports?  If so, be sure the interface resumes even if its
-                 * stub "device" node was never suspended.
-                 */
-                if (i)
-                        usb_autoresume_device(hdev, 0);
+                /* Autoresume */
+                ret = usb_autopm_get_interface(intf);
+                if (ret) {
+                        dev_dbg(hub_dev, "Can't autoresume: %d\n", ret);
+                        goto loop;
+                }
 
-                /* If this is an inactive or suspended hub, do nothing */
+                /* If this is an inactive hub, do nothing */
                 if (hub->quiescing)
-                        goto loop;
+                        goto loop_autopm;
 
                 if (hub->error) {
                         dev_dbg (hub_dev, "resetting for error %d\n",
@@ -2688,7 +2690,7 @@ static void hub_events(void)
                         if (ret) {
                                 dev_dbg (hub_dev,
                                         "error resetting hub: %d\n", ret);
-                                goto loop;
+                                goto loop_autopm;
                         }
 
                         hub->nerrors = 0;
@@ -2816,6 +2818,10 @@ static void hub_events(void)
                 if (!hdev->parent && !hub->busy_bits[0])
                         usb_enable_root_hub_irq(hdev->bus);
 
+loop_autopm:
+                /* Allow autosuspend if we're not going to run again */
+                if (list_empty(&hub->event_list))
+                        usb_autopm_enable(intf);
 loop:
                 usb_unlock_device(hdev);
                 usb_put_intf(intf);
@@ -2857,6 +2863,7 @@ static struct usb_driver hub_driver = {
         .post_reset =   hub_post_reset,
         .ioctl =        hub_ioctl,
         .id_table =     hub_id_table,
+        .supports_autosuspend = 1,
 };
 
 int usb_hub_init(void)