+ int i;
+ int num_configs;
+ 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.
+ */