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authorAlan Stern <stern@rowland.harvard.edu>2005-11-23 12:03:12 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2006-01-04 13:48:34 -0800
commit55c527187c9d78f840b284d596a0b298bc1493af (patch)
tree17f42fb911ecc70301f5a22d4c0e85ba7348a67a
parent949bf6431189c62eeebd3b52201406ba9978f525 (diff)
[PATCH] USB: Consider power budget when choosing configuration
This patch (as609) changes the way we keep track of power budgeting for USB hubs and devices, and it updates the choose_configuration routine to take this information into account. (This is something we should have been doing all along.) A new field in struct usb_device holds the amount of bus current available from the upstream port, and the usb_hub structure keeps track of the current available for each downstream port. Two new rules for configuration selection are added: Don't select a self-powered configuration when only bus power is available. Don't select a configuration requiring more bus power than is available. However the first rule is #if-ed out, because I found that the internal hub in my HP USB keyboard claims that its only configuration is self-powered. The rule would prevent the configuration from being chosen, leaving the hub & keyboard unconfigured. Since similar descriptor errors may turn out to be fairly common, it seemed wise not to include a rule that would break automatic configuration unnecessarily for such devices. The second rule may also trigger unnecessarily, although this should be less common. More likely it will annoy people by sometimes failing to accept configurations that should never have been chosen in the first place. The patch also changes usbcore's reaction when no configuration is suitable. Instead of raising an error and rejecting the device, now the core will simply leave the device unconfigured. People can always work around such problems by installing configurations manually through sysfs. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/core/hcd.c5
-rw-r--r--drivers/usb/core/hub.c229
-rw-r--r--drivers/usb/core/hub.h3
-rw-r--r--drivers/usb/core/message.c6
-rw-r--r--include/linux/usb.h2
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 */