5 files changed, 164 insertions, 81 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index d16a0e8a7d72..0018bbc4de34 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1825,8 +1825,6 @@ int usb_add_hcd(struct usb_hcd *hcd,
                 retval = -ENOMEM;
                 goto err_allocate_root_hub;
         }
-        rhdev->speed = (hcd->driver->flags & HCD_USB2) ? USB_SPEED_HIGH :
-                        USB_SPEED_FULL;
 
         /* Although in principle hcd->driver->start() might need to use rhdev,
          * none of the current drivers do.
@@ -1844,6 +1842,9 @@ int usb_add_hcd(struct usb_hcd *hcd,
                 dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
         hcd->remote_wakeup = hcd->can_wakeup;
 
+        rhdev->speed = (hcd->driver->flags & HCD_USB2) ? USB_SPEED_HIGH :
+                        USB_SPEED_FULL;
+        rhdev->bus_mA = min(500u, hcd->power_budget);
         if ((retval = register_root_hub(rhdev, hcd)) != 0)
                 goto err_register_root_hub;
 
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 895ac829b9cf..b311005ff1a6 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -702,26 +702,40 @@ static int hub_configure(struct usb_hub *hub,
          * and battery-powered root hubs (may provide just 8 mA).
          */
         ret = usb_get_status(hdev, USB_RECIP_DEVICE, 0, &hubstatus);
-        if (ret < 0) {
+        if (ret < 2) {
                 message = "can't get hub status";
                 goto fail;
         }
         le16_to_cpus(&hubstatus);
         if (hdev == hdev->bus->root_hub) {
-                struct usb_hcd *hcd =
-                                container_of(hdev->bus, struct usb_hcd, self);
-
-                hub->power_budget = min(500u, hcd->power_budget) / 2;
+                if (hdev->bus_mA == 0 || hdev->bus_mA >= 500)
+                        hub->mA_per_port = 500;
+                else {
+                        hub->mA_per_port = hdev->bus_mA;
+                        hub->limited_power = 1;
+                }
         } else if ((hubstatus & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
                 dev_dbg(hub_dev, "hub controller current requirement: %dmA\n",
                         hub->descriptor->bHubContrCurrent);
-                hub->power_budget = (501 - hub->descriptor->bHubContrCurrent)
-                                        / 2;
+                hub->limited_power = 1;
+                if (hdev->maxchild > 0) {
+                        int remaining = hdev->bus_mA -
+                                        hub->descriptor->bHubContrCurrent;
+
+                        if (remaining < hdev->maxchild * 100)
+                                dev_warn(hub_dev,
+                                        "insufficient power available "
+                                        "to use all downstream ports\n");
+                        hub->mA_per_port = 100;         /* 7.2.1.1 */
+                }
+        } else {        /* Self-powered external hub */
+                /* FIXME: What about battery-powered external hubs that
+                 * provide less current per port? */
+                hub->mA_per_port = 500;
         }
-        if (hub->power_budget)
-                dev_dbg(hub_dev, "%dmA bus power budget for children\n",
-                        hub->power_budget * 2);
-
+        if (hub->mA_per_port < 500)
+                dev_dbg(hub_dev, "%umA bus power budget for each child\n",
+                                hub->mA_per_port);
 
         ret = hub_hub_status(hub, &hubstatus, &hubchange);
         if (ret < 0) {
@@ -1136,45 +1150,107 @@ void usb_disconnect(struct usb_device **pdev)
         device_unregister(&udev->dev);
 }
 
+static inline const char *plural(int n)
+{
+        return (n == 1 ? "" : "s");
+}
+
 static int choose_configuration(struct usb_device *udev)
 {
-        int c, i;
+        int i;
+        u16 devstatus;
+        int bus_powered;
+        int num_configs;
+        struct usb_host_config *c, *best;
+
+        /* If this fails, assume the device is bus-powered */
+        devstatus = 0;
+        usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
+        le16_to_cpus(&devstatus);
+        bus_powered = ((devstatus & (1 << USB_DEVICE_SELF_POWERED)) == 0);
+        dev_dbg(&udev->dev, "device is %s-powered\n",
+                        bus_powered ? "bus" : "self");
+
+        best = NULL;
+        c = udev->config;
+        num_configs = udev->descriptor.bNumConfigurations;
+        for (i = 0; i < num_configs; (i++, c++)) {
+                struct usb_interface_descriptor *desc =
+                                &c->intf_cache[0]->altsetting->desc;
+
+                /*
+                 * HP's USB bus-powered keyboard has only one configuration
+                 * and it claims to be self-powered; other devices may have
+                 * similar errors in their descriptors.  If the next test
+                 * were allowed to execute, such configurations would always
+                 * be rejected and the devices would not work as expected.
+                 */
+#if 0
+                /* Rule out self-powered configs for a bus-powered device */
+                if (bus_powered && (c->desc.bmAttributes &
+                                        USB_CONFIG_ATT_SELFPOWER))
+                        continue;
+#endif
 
-        /* NOTE: this should interact with hub power budgeting */
+                /*
+                 * The next test may not be as effective as it should be.
+                 * Some hubs have errors in their descriptor, claiming
+                 * to be self-powered when they are really bus-powered.
+                 * We will overestimate the amount of current such hubs
+                 * make available for each port.
+                 *
+                 * This is a fairly benign sort of failure.  It won't
+                 * cause us to reject configurations that we should have
+                 * accepted.
+                 */
 
-        c = udev->config[0].desc.bConfigurationValue;
-        if (udev->descriptor.bNumConfigurations != 1) {
-                for (i = 0; i < udev->descriptor.bNumConfigurations; i++) {
-                        struct usb_interface_descriptor *desc;
+                /* Rule out configs that draw too much bus current */
+                if (c->desc.bMaxPower * 2 > udev->bus_mA)
+                        continue;
 
-                        /* heuristic:  Linux is more likely to have class
-                         * drivers, so avoid vendor-specific interfaces.
-                         */
-                        desc = &udev->config[i].intf_cache[0]
-                                        ->altsetting->desc;
-                        if (desc->bInterfaceClass == USB_CLASS_VENDOR_SPEC)
-                                continue;
-                        /* COMM/2/all is CDC ACM, except 0xff is MSFT RNDIS.
-                         * MSFT needs this to be the first config; never use
-                         * it as the default unless Linux has host-side RNDIS.
-                         * A second config would ideally be CDC-Ethernet, but
-                         * may instead be the "vendor specific" CDC subset
-                         * long used by ARM Linux for sa1100 or pxa255.
-                         */
-                        if (desc->bInterfaceClass == USB_CLASS_COMM
-                                        && desc->bInterfaceSubClass == 2
-                                        && desc->bInterfaceProtocol == 0xff) {
-                                c = udev->config[1].desc.bConfigurationValue;
-                                continue;
-                        }
-                        c = udev->config[i].desc.bConfigurationValue;
+                /* If the first config's first interface is COMM/2/0xff
+                 * (MSFT RNDIS), rule it out unless Linux has host-side
+                 * RNDIS support. */
+                if (i == 0 && desc->bInterfaceClass == USB_CLASS_COMM
+                                && desc->bInterfaceSubClass == 2
+                                && desc->bInterfaceProtocol == 0xff) {
+#ifndef CONFIG_USB_NET_RNDIS
+                        continue;
+#else
+                        best = c;
+#endif
+                }
+
+                /* From the remaining configs, choose the first one whose
+                 * first interface is for a non-vendor-specific class.
+                 * Reason: Linux is more likely to have a class driver
+                 * than a vendor-specific driver. */
+                else if (udev->descriptor.bDeviceClass !=
+                                                USB_CLASS_VENDOR_SPEC &&
+                                desc->bInterfaceClass !=
+                                                USB_CLASS_VENDOR_SPEC) {
+                        best = c;
                         break;
                 }
+
+                /* If all the remaining configs are vendor-specific,
+                 * choose the first one. */
+                else if (!best)
+                        best = c;
+        }
+
+        if (best) {
+                i = best->desc.bConfigurationValue;
                 dev_info(&udev->dev,
-                        "configuration #%d chosen from %d choices\n",
-                        c, udev->descriptor.bNumConfigurations);
+                        "configuration #%d chosen from %d choice%s\n",
+                        i, num_configs, plural(num_configs));
+        } else {
+                i = -1;
+                dev_warn(&udev->dev,
+                        "no configuration chosen from %d choice%s\n",
+                        num_configs, plural(num_configs));
         }
-        return c;
+        return i;
 }
 
 #ifdef DEBUG
@@ -1327,17 +1403,13 @@ int usb_new_device(struct usb_device *udev)
          * with the driver core, and lets usb device drivers bind to them.
          */
         c = choose_configuration(udev);
-        if (c < 0)
-                dev_warn(&udev->dev,
-                                "can't choose an initial configuration\n");
-        else {
+        if (c >= 0) {
                 err = usb_set_configuration(udev, c);
                 if (err) {
                         dev_err(&udev->dev, "can't set config #%d, error %d\n",
                                         c, err);
-                        usb_remove_sysfs_dev_files(udev);
-                        device_del(&udev->dev);
-                        goto fail;
+                        /* This need not be fatal.  The user can try to
+                         * set other configurations. */
                 }
         }
 
@@ -1702,7 +1774,7 @@ static int finish_device_resume(struct usb_device *udev)
          * and device drivers will know about any resume quirks.
          */
         status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
-        if (status < 0)
+        if (status < 2)
                 dev_dbg(&udev->dev,
                         "gone after usb resume? status %d\n",
                         status);
@@ -1711,7 +1783,7 @@ static int finish_device_resume(struct usb_device *udev)
                 int             (*resume)(struct device *);
 
                 le16_to_cpus(&devstatus);
-                if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)
+                if ((devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))
                                 && udev->parent) {
                         status = usb_control_msg(udev,
                                         usb_sndctrlpipe(udev, 0),
@@ -2374,39 +2446,36 @@ hub_power_remaining (struct usb_hub *hub)
 {
         struct usb_device *hdev = hub->hdev;
         int remaining;
-        unsigned i;
+        int port1;
 
-        remaining = hub->power_budget;
-        if (!remaining)         /* self-powered */
+        if (!hub->limited_power)
                 return 0;
 
-        for (i = 0; i < hdev->maxchild; i++) {
-                struct usb_device       *udev = hdev->children[i];
-                int                     delta, ceiling;
+        remaining = hdev->bus_mA - hub->descriptor->bHubContrCurrent;
+        for (port1 = 1; port1 <= hdev->maxchild; ++port1) {
+                struct usb_device       *udev = hdev->children[port1 - 1];
+                int                     delta;
 
                 if (!udev)
                         continue;
 
-                /* 100mA per-port ceiling, or 8mA for OTG ports */
-                if (i != (udev->bus->otg_port - 1) || hdev->parent)
-                        ceiling = 50;
-                else
-                        ceiling = 4;
-
+                /* Unconfigured devices may not use more than 100mA,
+                 * or 8mA for OTG ports */
                 if (udev->actconfig)
-                        delta = udev->actconfig->desc.bMaxPower;
+                        delta = udev->actconfig->desc.bMaxPower * 2;
+                else if (port1 != udev->bus->otg_port || hdev->parent)
+                        delta = 100;
                 else
-                        delta = ceiling;
-                // dev_dbg(&udev->dev, "budgeted %dmA\n", 2 * delta);
-                if (delta > ceiling)
-                        dev_warn(&udev->dev, "%dmA over %dmA budget!\n",
-                                2 * (delta - ceiling), 2 * ceiling);
+                        delta = 8;
+                if (delta > hub->mA_per_port)
+                        dev_warn(&udev->dev, "%dmA is over %umA budget "
+                                        "for port %d!\n",
+                                        delta, hub->mA_per_port, port1);
                 remaining -= delta;
         }
         if (remaining < 0) {
-                dev_warn(hub->intfdev,
-                        "%dmA over power budget!\n",
-                        -2 * remaining);
+                dev_warn(hub->intfdev, "%dmA over power budget!\n",
+                        - remaining);
                 remaining = 0;
         }
         return remaining;
@@ -2501,7 +2570,8 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 
                 usb_set_device_state(udev, USB_STATE_POWERED);
                 udev->speed = USB_SPEED_UNKNOWN;
- 
+                udev->bus_mA = hub->mA_per_port;
+
                 /* set the address */
                 choose_address(udev);
                 if (udev->devnum <= 0) {
@@ -2521,16 +2591,16 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
                  * on the parent.
                  */
                 if (udev->descriptor.bDeviceClass == USB_CLASS_HUB
-                                && hub->power_budget) {
+                                && udev->bus_mA <= 100) {
                         u16     devstat;
 
                         status = usb_get_status(udev, USB_RECIP_DEVICE, 0,
                                         &devstat);
-                        if (status < 0) {
+                        if (status < 2) {
                                 dev_dbg(&udev->dev, "get status %d ?\n", status);
                                 goto loop_disable;
                         }
-                        cpu_to_le16s(&devstat);
+                        le16_to_cpus(&devstat);
                         if ((devstat & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
                                 dev_err(&udev->dev,
                                         "can't connect bus-powered hub "
@@ -2583,9 +2653,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 
                 status = hub_power_remaining(hub);
                 if (status)
-                        dev_dbg(hub_dev,
-                                "%dmA power budget left\n",
-                                2 * status);
+                        dev_dbg(hub_dev, "%dmA power budget left\n", status);
 
                 return;
 
@@ -2797,6 +2865,11 @@ static void hub_events(void)
                         if (hubchange & HUB_CHANGE_LOCAL_POWER) {
                                 dev_dbg (hub_dev, "power change\n");
                                 clear_hub_feature(hdev, C_HUB_LOCAL_POWER);
+                                if (hubstatus & HUB_STATUS_LOCAL_POWER)
+                                        /* FIXME: Is this always true? */
+                                        hub->limited_power = 0;
+                                else
+                                        hub->limited_power = 1;
                         }
                         if (hubchange & HUB_CHANGE_OVERCURRENT) {
                                 dev_dbg (hub_dev, "overcurrent change\n");
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index bf23f8978024..29d5f45a8456 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -220,8 +220,9 @@ struct usb_hub {
         struct usb_hub_descriptor *descriptor;  /* class descriptor */
         struct usb_tt           tt;             /* Transaction Translator */
 
-        u8                      power_budget;   /* in 2mA units; or zero */
+        unsigned                mA_per_port;    /* current for each child */
 
+        unsigned                limited_power:1;
         unsigned                quiescing:1;
         unsigned                activating:1;
         unsigned                resume_root_hub:1;
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index fe74f99ca5f4..99ab774d4fdb 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1387,6 +1387,12 @@ free_interfaces:
         if (dev->state != USB_STATE_ADDRESS)
                 usb_disable_device (dev, 1);    // Skip ep0
 
+        n = dev->bus_mA - cp->desc.bMaxPower * 2;
+        if (n < 0)
+                dev_warn(&dev->dev, "new config #%d exceeds power "
+                                "limit by %dmA\n",
+                                configuration, -n);
+
         if ((ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                         USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
                         NULL, 0, USB_CTRL_SET_TIMEOUT)) < 0)
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 46dc0421d19e..27575e678a7c 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -347,6 +347,8 @@ struct usb_device {
 
         char **rawdescriptors;          /* Raw descriptors for each config */
 
+        unsigned short bus_mA;          /* Current available from the bus */
+
         int have_langid;                /* whether string_langid is valid */
         int string_langid;              /* language ID for strings */