diff options
Diffstat (limited to 'drivers/usb/core/generic.c')
| -rw-r--r-- | drivers/usb/core/generic.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c index fa6f34a12b4..1522195de71 100644 --- a/drivers/usb/core/generic.c +++ b/drivers/usb/core/generic.c @@ -21,24 +21,208 @@ #include <linux/usb.h> #include "usb.h" +static inline const char *plural(int n) +{ + return (n == 1 ? "" : "s"); +} + +static int choose_configuration(struct usb_device *udev) +{ + int i; + int num_configs; + int insufficient_power = 0; + struct usb_host_config *c, *best; + + best = NULL; + c = udev->config; + num_configs = udev->descriptor.bNumConfigurations; + for (i = 0; i < num_configs; (i++, c++)) { + struct usb_interface_descriptor *desc = NULL; + + /* It's possible that a config has no interfaces! */ + if (c->desc.bNumInterfaces > 0) + 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. + * In the meantime, we run the risk of selecting a config + * that requires external power at a time when that power + * isn't available. It seems to be the lesser of two evils. + * + * Bugzilla #6448 reports a device that appears to crash + * when it receives a GET_DEVICE_STATUS request! We don't + * have any other way to tell whether a device is self-powered, + * but since we don't use that information anywhere but here, + * the call has been removed. + * + * Maybe the GET_DEVICE_STATUS call and the test below can + * be reinstated when device firmwares become more reliable. + * Don't hold your breath. + */ +#if 0 + /* Rule out self-powered configs for a bus-powered device */ + if (bus_powered && (c->desc.bmAttributes & + USB_CONFIG_ATT_SELFPOWER)) + continue; +#endif + + /* + * 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. + */ + + /* Rule out configs that draw too much bus current */ + if (c->desc.bMaxPower * 2 > udev->bus_mA) { + insufficient_power++; + continue; + } + + /* 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 + && desc->bInterfaceClass == USB_CLASS_COMM + && desc->bInterfaceSubClass == 2 + && desc->bInterfaceProtocol == 0xff) { +#ifndef CONFIG_USB_NET_RNDIS_HOST + 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 || 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 (insufficient_power > 0) + dev_info(&udev->dev, "rejected %d configuration%s " + "due to insufficient available bus power\n", + insufficient_power, plural(insufficient_power)); + + if (best) { + i = best->desc.bConfigurationValue; + dev_info(&udev->dev, + "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 i; +} + static int generic_probe(struct usb_device *udev) { + int err, c; + + /* put device-specific files into sysfs */ + usb_create_sysfs_dev_files(udev); + + /* Choose and set the configuration. This registers the interfaces + * with the driver core and lets interface drivers bind to them. + */ + c = choose_configuration(udev); + 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); + /* This need not be fatal. The user can try to + * set other configurations. */ + } + } + + /* USB device state == configured ... usable */ + usb_notify_add_device(udev); + return 0; } + static void generic_disconnect(struct usb_device *udev) { + usb_notify_remove_device(udev); + /* if this is only an unbind, not a physical disconnect, then * unconfigure the device */ if (udev->state == USB_STATE_CONFIGURED) usb_set_configuration(udev, 0); + usb_remove_sysfs_dev_files(udev); + /* in case the call failed or the device was suspended */ if (udev->state >= USB_STATE_CONFIGURED) usb_disable_device(udev, 0); } +#ifdef CONFIG_PM + +static int verify_suspended(struct device *dev, void *unused) +{ + if (dev->driver == NULL) + return 0; + return (dev->power.power_state.event == PM_EVENT_ON) ? -EBUSY : 0; +} + +static int generic_suspend(struct usb_device *udev, pm_message_t msg) +{ + int status; + + /* rule out bogus requests through sysfs */ + status = device_for_each_child(&udev->dev, NULL, verify_suspended); + if (status) + return status; + + /* USB devices enter SUSPEND state through their hubs, but can be + * marked for FREEZE as soon as their children are already idled. + * But those semantics are useless, so we equate the two (sigh). + */ + return usb_port_suspend(udev); +} + +static int generic_resume(struct usb_device *udev) +{ + if (udev->state == USB_STATE_NOTATTACHED) + return 0; + + return usb_port_resume(udev); +} + +#endif /* CONFIG_PM */ + struct usb_device_driver usb_generic_driver = { .name = "usb", .probe = generic_probe, .disconnect = generic_disconnect, +#ifdef CONFIG_PM + .suspend = generic_suspend, + .resume = generic_resume, +#endif }; |