2 * drivers/usb/generic.c - generic driver for USB devices (not interfaces)
4 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
6 * based on drivers/usb/usb.c which had the following copyrights:
7 * (C) Copyright Linus Torvalds 1999
8 * (C) Copyright Johannes Erdfelt 1999-2001
9 * (C) Copyright Andreas Gal 1999
10 * (C) Copyright Gregory P. Smith 1999
11 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
12 * (C) Copyright Randy Dunlap 2000
13 * (C) Copyright David Brownell 2000-2004
14 * (C) Copyright Yggdrasil Computing, Inc. 2000
15 * (usb_device_id matching changes by Adam J. Richter)
16 * (C) Copyright Greg Kroah-Hartman 2002-2003
20 #include <linux/usb.h>
23 static inline const char *plural(int n
)
25 return (n
== 1 ? "" : "s");
28 static int choose_configuration(struct usb_device
*udev
)
32 int insufficient_power
= 0;
33 struct usb_host_config
*c
, *best
;
37 num_configs
= udev
->descriptor
.bNumConfigurations
;
38 for (i
= 0; i
< num_configs
; (i
++, c
++)) {
39 struct usb_interface_descriptor
*desc
= NULL
;
41 /* It's possible that a config has no interfaces! */
42 if (c
->desc
.bNumInterfaces
> 0)
43 desc
= &c
->intf_cache
[0]->altsetting
->desc
;
46 * HP's USB bus-powered keyboard has only one configuration
47 * and it claims to be self-powered; other devices may have
48 * similar errors in their descriptors. If the next test
49 * were allowed to execute, such configurations would always
50 * be rejected and the devices would not work as expected.
51 * In the meantime, we run the risk of selecting a config
52 * that requires external power at a time when that power
53 * isn't available. It seems to be the lesser of two evils.
55 * Bugzilla #6448 reports a device that appears to crash
56 * when it receives a GET_DEVICE_STATUS request! We don't
57 * have any other way to tell whether a device is self-powered,
58 * but since we don't use that information anywhere but here,
59 * the call has been removed.
61 * Maybe the GET_DEVICE_STATUS call and the test below can
62 * be reinstated when device firmwares become more reliable.
63 * Don't hold your breath.
66 /* Rule out self-powered configs for a bus-powered device */
67 if (bus_powered
&& (c
->desc
.bmAttributes
&
68 USB_CONFIG_ATT_SELFPOWER
))
73 * The next test may not be as effective as it should be.
74 * Some hubs have errors in their descriptor, claiming
75 * to be self-powered when they are really bus-powered.
76 * We will overestimate the amount of current such hubs
77 * make available for each port.
79 * This is a fairly benign sort of failure. It won't
80 * cause us to reject configurations that we should have
84 /* Rule out configs that draw too much bus current */
85 if (c
->desc
.bMaxPower
* 2 > udev
->bus_mA
) {
90 /* If the first config's first interface is COMM/2/0xff
91 * (MSFT RNDIS), rule it out unless Linux has host-side
94 && desc
->bInterfaceClass
== USB_CLASS_COMM
95 && desc
->bInterfaceSubClass
== 2
96 && desc
->bInterfaceProtocol
== 0xff) {
97 #ifndef CONFIG_USB_NET_RNDIS_HOST
104 /* From the remaining configs, choose the first one whose
105 * first interface is for a non-vendor-specific class.
106 * Reason: Linux is more likely to have a class driver
107 * than a vendor-specific driver. */
108 else if (udev
->descriptor
.bDeviceClass
!=
109 USB_CLASS_VENDOR_SPEC
&&
110 (!desc
|| desc
->bInterfaceClass
!=
111 USB_CLASS_VENDOR_SPEC
)) {
116 /* If all the remaining configs are vendor-specific,
117 * choose the first one. */
122 if (insufficient_power
> 0)
123 dev_info(&udev
->dev
, "rejected %d configuration%s "
124 "due to insufficient available bus power\n",
125 insufficient_power
, plural(insufficient_power
));
128 i
= best
->desc
.bConfigurationValue
;
130 "configuration #%d chosen from %d choice%s\n",
131 i
, num_configs
, plural(num_configs
));
135 "no configuration chosen from %d choice%s\n",
136 num_configs
, plural(num_configs
));
141 static int generic_probe(struct usb_device
*udev
)
145 /* put device-specific files into sysfs */
146 usb_create_sysfs_dev_files(udev
);
148 /* Choose and set the configuration. This registers the interfaces
149 * with the driver core and lets interface drivers bind to them.
151 c
= choose_configuration(udev
);
153 err
= usb_set_configuration(udev
, c
);
155 dev_err(&udev
->dev
, "can't set config #%d, error %d\n",
157 /* This need not be fatal. The user can try to
158 * set other configurations. */
162 /* USB device state == configured ... usable */
163 usb_notify_add_device(udev
);
168 static void generic_disconnect(struct usb_device
*udev
)
170 usb_notify_remove_device(udev
);
172 /* if this is only an unbind, not a physical disconnect, then
173 * unconfigure the device */
175 usb_set_configuration(udev
, 0);
177 usb_remove_sysfs_dev_files(udev
);
182 static int generic_suspend(struct usb_device
*udev
, pm_message_t msg
)
184 /* USB devices enter SUSPEND state through their hubs, but can be
185 * marked for FREEZE as soon as their children are already idled.
186 * But those semantics are useless, so we equate the two (sigh).
188 return usb_port_suspend(udev
);
191 static int generic_resume(struct usb_device
*udev
)
193 return usb_port_resume(udev
);
196 #endif /* CONFIG_PM */
198 struct usb_device_driver usb_generic_driver
= {
200 .probe
= generic_probe
,
201 .disconnect
= generic_disconnect
,
203 .suspend
= generic_suspend
,
204 .resume
= generic_resume
,
206 .supports_autosuspend
= 1,