[PATCH] usb_interface power state

This updates the handling of power state for USB interfaces.

  - Formalizes an existing invariant:  interface "power state" is a boolean:
    ON when I/O is allowed, and FREEZE otherwise.  It does so by defining
    some inlined helpers, then using them.

  - Adds a useful invariant:  the only interfaces marked active are those
    bound to non-suspended drivers.  Later patches build on this invariant.

  - Simplifies the interface driver API (and removes some error paths) by
    removing the requirement that they record power state changes during
    suspend and resume callbacks.  Now usbcore does that.

A few drivers were simplified to address that last change.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
 drivers/usb/core/hub.c       |   33 +++++++++------------
 drivers/usb/core/message.c   |    1
 drivers/usb/core/usb.c       |   65 +++++++++++++++++++++++++++++++++----------
 drivers/usb/core/usb.h       |   18 +++++++++++
 drivers/usb/input/hid-core.c |    2 -
 drivers/usb/misc/usbtest.c   |   10 ------
 drivers/usb/net/pegasus.c    |    2 -
 drivers/usb/net/usbnet.c     |    2 -
 8 files changed, 85 insertions(+), 48 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c3e2024..61341d2 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1624,7 +1624,7 @@ static int __usb_suspend_device (struct usb_device *udev, int port1,
                        struct usb_driver       *driver;
 
                        intf = udev->actconfig->interface[i];
-                       if (state.event <= intf->dev.power.power_state.event)
+                       if (!is_active(intf))
                                continue;
                        if (!intf->dev.driver)
                                continue;
@@ -1632,11 +1632,12 @@ static int __usb_suspend_device (struct usb_device *udev, int port1,
 
                        if (driver->suspend) {
                                status = driver->suspend(intf, state);
-                               if (intf->dev.power.power_state.event != state.event
-                                               || status)
+                               if (status == 0)
+                                       mark_quiesced(intf);
+                               else
                                        dev_err(&intf->dev,
-                                               "suspend %d fail, code %d\n",
-                                               state.event, status);
+                                               "suspend error %d\n",
+                                               status);
                        }
 
                        /* only drivers with suspend() can ever resume();
@@ -1787,7 +1788,7 @@ static int finish_port_resume(struct usb_device *udev)
                        struct usb_driver       *driver;
 
                        intf = udev->actconfig->interface[i];
-                       if (intf->dev.power.power_state.event == PM_EVENT_ON)
+                       if (is_active(intf))
                                continue;
                        if (!intf->dev.driver) {
                                /* FIXME maybe force to alt 0 */
@@ -1800,12 +1801,14 @@ static int finish_port_resume(struct usb_device *udev)
                                continue;
 
                        /* can we do better than just logging errors? */
+                       mark_active(intf);
                        status = driver->resume(intf);
-                       if (intf->dev.power.power_state.event != PM_EVENT_ON
-                                       || status)
+                       if (status < 0) {
+                               mark_quiesced(intf);
                                dev_dbg(&intf->dev,
-                                       "resume fail, state %d code %d\n",
-                                       intf->dev.power.power_state.event, status);
+                                       "resume error %d\n",
+                                       status);
+                       }
                }
                status = 0;
 
@@ -1952,7 +1955,7 @@ static int remote_wakeup(struct usb_device *udev)
        return status;
 }
 
-static int hub_suspend(struct usb_interface *intf, pm_message_t state)
+static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
 {
        struct usb_hub          *hub = usb_get_intfdata (intf);
        struct usb_device       *hdev = hub->hdev;
@@ -1970,14 +1973,13 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t state)
                if (!udev)
                        continue;
                down(&udev->serialize);
-               status = __usb_suspend_device(udev, port1, state);
+               status = __usb_suspend_device(udev, port1, msg);
                up(&udev->serialize);
                if (status < 0)
                        dev_dbg(&intf->dev, "suspend port %d --> %d\n",
                                port1, status);
        }
 
-       intf->dev.power.power_state = state;
        return 0;
 }
 
@@ -1988,9 +1990,6 @@ static int hub_resume(struct usb_interface *intf)
        unsigned                port1;
        int                     status;
 
-       if (intf->dev.power.power_state.event == PM_EVENT_ON)
-               return 0;
-
        for (port1 = 1; port1 <= hdev->maxchild; port1++) {
                struct usb_device       *udev;
                u16                     portstat, portchange;
@@ -2024,8 +2023,6 @@ static int hub_resume(struct usb_interface *intf)
                }
                up(&udev->serialize);
        }
-       intf->dev.power.power_state = PMSG_ON;
-
        hub->resume_root_hub = 0;
        hub_activate(hub);
        return 0;

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index f9a81e8..ebf59ea 100644 (file)
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1393,6 +1393,7 @@ free_interfaces:
                        intf->dev.dma_mask = dev->dev.dma_mask;
                        intf->dev.release = release_interface;
                        device_initialize (&intf->dev);
+                       mark_quiesced(intf);
                        sprintf (&intf->dev.bus_id[0], "%d-%s:%d.%d",
                                 dev->bus->busnum, dev->devpath,
                                 configuration,

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 4c57f3f..6ecfdce 100644 (file)
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -107,10 +107,19 @@ static int usb_probe_interface(struct device *dev)
        id = usb_match_id (intf, driver->id_table);
        if (id) {
                dev_dbg (dev, "%s - got id\n", __FUNCTION__);
+
+               /* Interface "power state" doesn't correspond to any hardware
+                * state whatsoever.  We use it to record when it's bound to
+                * a driver that may start I/0:  it's not frozen/quiesced.
+                */
+               mark_active(intf);
                intf->condition = USB_INTERFACE_BINDING;
                error = driver->probe (intf, id);
-               intf->condition = error ? USB_INTERFACE_UNBOUND :
-                               USB_INTERFACE_BOUND;
+               if (error) {
+                       mark_quiesced(intf);
+                       intf->condition = USB_INTERFACE_UNBOUND;
+               } else
+                       intf->condition = USB_INTERFACE_BOUND;
        }
 
        return error;
@@ -136,6 +145,7 @@ static int usb_unbind_interface(struct device *dev)
                        0);
        usb_set_intfdata(intf, NULL);
        intf->condition = USB_INTERFACE_UNBOUND;
+       mark_quiesced(intf);
 
        return 0;
 }
@@ -299,6 +309,7 @@ int usb_driver_claim_interface(struct usb_driver *driver,
        dev->driver = &driver->driver;
        usb_set_intfdata(iface, priv);
        iface->condition = USB_INTERFACE_BOUND;
+       mark_active(iface);
 
        /* if interface was already added, bind now; else let
         * the future device_add() bind it, bypassing probe()
@@ -345,6 +356,7 @@ void usb_driver_release_interface(struct usb_driver *driver,
        dev->driver = NULL;
        usb_set_intfdata(iface, NULL);
        iface->condition = USB_INTERFACE_UNBOUND;
+       mark_quiesced(iface);
 }
 
 /**
@@ -1404,8 +1416,9 @@ void usb_buffer_unmap_sg (struct usb_device *dev, unsigned pipe,
 
 static int usb_generic_suspend(struct device *dev, pm_message_t message)
 {
-       struct usb_interface *intf;
-       struct usb_driver *driver;
+       struct usb_interface    *intf;
+       struct usb_driver       *driver;
+       int                     status;
 
        if (dev->driver == &usb_generic_driver)
                return usb_suspend_device (to_usb_device(dev), message);
@@ -1417,21 +1430,34 @@ static int usb_generic_suspend(struct device *dev, pm_message_t message)
        intf = to_usb_interface(dev);
        driver = to_usb_driver(dev->driver);
 
-       /* there's only one USB suspend state */
-       if (intf->dev.power.power_state.event)
+       /* with no hardware, USB interfaces only use FREEZE and ON states */
+       if (!is_active(intf))
                return 0;
 
-       if (driver->suspend)
-               return driver->suspend(intf, message);
-       return 0;
+       if (driver->suspend && driver->resume) {
+               status = driver->suspend(intf, message);
+               if (status)
+                       dev_err(dev, "%s error %d\n", "suspend", status);
+               else
+                       mark_quiesced(intf);
+       } else {
+               // FIXME else if there's no suspend method, disconnect...
+               dev_warn(dev, "no %s?\n", "suspend");
+               status = 0;
+       }
+       return status;
 }
 
 static int usb_generic_resume(struct device *dev)
 {
-       struct usb_interface *intf;
-       struct usb_driver *driver;
+       struct usb_interface    *intf;
+       struct usb_driver       *driver;
+       int                     status;
+
+       if (dev->power.power_state.event == PM_EVENT_ON)
+               return 0;
 
-       /* devices resume through their hub */
+       /* devices resume through their hubs */
        if (dev->driver == &usb_generic_driver)
                return usb_resume_device (to_usb_device(dev));
 
@@ -1442,8 +1468,19 @@ static int usb_generic_resume(struct device *dev)
        intf = to_usb_interface(dev);
        driver = to_usb_driver(dev->driver);
 
-       if (driver->resume)
-               return driver->resume(intf);
+       /* if driver was suspended, it has a resume method;
+        * however, sysfs can wrongly mark things as suspended
+        * (on the "no suspend method" FIXME path above)
+        */
+       mark_active(intf);
+       if (driver->resume) {
+               status = driver->resume(intf);
+               if (status) {
+                       dev_err(dev, "%s error %d\n", "resume", status);
+                       mark_quiesced(intf);
+               }
+       } else
+               dev_warn(dev, "no %s?\n", "resume");
        return 0;
 }
 

diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index e6504f3..3741a99 100644 (file)
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -28,6 +28,24 @@ extern void usb_major_cleanup(void);
 extern int usb_host_init(void);
 extern void usb_host_cleanup(void);
 
+/* Interfaces and their "power state" are owned by usbcore */
+
+static inline void mark_active(struct usb_interface *f)
+{
+       f->dev.power.power_state.event = PM_EVENT_ON;
+}
+
+static inline void mark_quiesced(struct usb_interface *f)
+{
+       f->dev.power.power_state.event = PM_EVENT_FREEZE;
+}
+
+static inline int is_active(struct usb_interface *f)
+{
+       return f->dev.power.power_state.event == PM_EVENT_ON;
+}
+
+
 /* for labeling diagnostics */
 extern const char *usbcore_name;
 

diff --git a/drivers/usb/input/hid-core.c b/drivers/usb/input/hid-core.c
index 411a064..f7fcce7 100644 (file)
--- a/drivers/usb/input/hid-core.c
+++ b/drivers/usb/input/hid-core.c
@@ -1887,7 +1887,6 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message)
        struct hid_device *hid = usb_get_intfdata (intf);
 
        usb_kill_urb(hid->urbin);
-       intf->dev.power.power_state = PMSG_SUSPEND;
        dev_dbg(&intf->dev, "suspend\n");
        return 0;
 }
@@ -1897,7 +1896,6 @@ static int hid_resume(struct usb_interface *intf)
        struct hid_device *hid = usb_get_intfdata (intf);
        int status;
 
-       intf->dev.power.power_state = PMSG_ON;
        if (hid->open)
                status = usb_submit_urb(hid->urbin, GFP_NOIO);
        else

diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index 54799eb..d055196 100644 (file)
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -1948,21 +1948,11 @@ usbtest_probe (struct usb_interface *intf, const struct usb_device_id *id)
 
 static int usbtest_suspend (struct usb_interface *intf, pm_message_t message)
 {
-       struct usbtest_dev      *dev = usb_get_intfdata (intf);
-
-       down (&dev->sem);
-       intf->dev.power.power_state = PMSG_SUSPEND;
-       up (&dev->sem);
        return 0;
 }
 
 static int usbtest_resume (struct usb_interface *intf)
 {
-       struct usbtest_dev      *dev = usb_get_intfdata (intf);
-
-       down (&dev->sem);
-       intf->dev.power.power_state = PMSG_ON;
-       up (&dev->sem);
        return 0;
 }
 

diff --git a/drivers/usb/net/pegasus.c b/drivers/usb/net/pegasus.c
index 6a4ffe6..537eb18 100644 (file)
--- a/drivers/usb/net/pegasus.c
+++ b/drivers/usb/net/pegasus.c
@@ -1384,7 +1384,6 @@ static int pegasus_suspend (struct usb_interface *intf, pm_message_t message)
                usb_kill_urb(pegasus->rx_urb);
                usb_kill_urb(pegasus->intr_urb);
        }
-       intf->dev.power.power_state = PMSG_SUSPEND;
        return 0;
 }
 
@@ -1392,7 +1391,6 @@ static int pegasus_resume (struct usb_interface *intf)
 {
        struct pegasus *pegasus = usb_get_intfdata(intf);
 
-       intf->dev.power.power_state = PMSG_ON;
        netif_device_attach (pegasus->net);
        if (netif_running(pegasus->net)) {
                pegasus->rx_urb->status = 0;

diff --git a/drivers/usb/net/usbnet.c b/drivers/usb/net/usbnet.c
index fce81d7..74f05c9 100644 (file)
--- a/drivers/usb/net/usbnet.c
+++ b/drivers/usb/net/usbnet.c
@@ -1185,7 +1185,6 @@ int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
        netif_device_detach (dev->net);
        (void) unlink_urbs (dev, &dev->rxq);
        (void) unlink_urbs (dev, &dev->txq);
-       intf->dev.power.power_state = PMSG_SUSPEND;
        return 0;
 }
 EXPORT_SYMBOL_GPL(usbnet_suspend);
@@ -1194,7 +1193,6 @@ int usbnet_resume (struct usb_interface *intf)
 {
        struct usbnet           *dev = usb_get_intfdata(intf);
 
-       intf->dev.power.power_state = PMSG_ON;
        netif_device_attach (dev->net);
        tasklet_schedule (&dev->bh);
        return 0;