In a couple of places, usbcore assumes that a USB device configuration
will have a nonzero number of interfaces. Having no interfaces may or may
not be allowed by the USB spec; in any event we shouldn't die if we
encounter such a thing. This patch (as662) removes the assumptions.
Signed-off-by: Alan Stern <[EMAIL PROTECTED]>
---
Index: usb-2.6/drivers/usb/core/hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/hub.c
+++ usb-2.6/drivers/usb/core/hub.c
@@ -1179,8 +1179,11 @@ static int choose_configuration(struct u
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;
+ 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
@@ -1215,7 +1218,8 @@ static int choose_configuration(struct u
/* 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
+ if (i == 0 && desc
+ && desc->bInterfaceClass == USB_CLASS_COMM
&& desc->bInterfaceSubClass == 2
&& desc->bInterfaceProtocol == 0xff) {
#ifndef CONFIG_USB_NET_RNDIS
@@ -1231,8 +1235,8 @@ static int choose_configuration(struct u
* than a vendor-specific driver. */
else if (udev->descriptor.bDeviceClass !=
USB_CLASS_VENDOR_SPEC &&
- desc->bInterfaceClass !=
- USB_CLASS_VENDOR_SPEC) {
+ (!desc || desc->bInterfaceClass !=
+ USB_CLASS_VENDOR_SPEC)) {
best = c;
break;
}
@@ -3022,7 +3026,7 @@ int usb_reset_device(struct usb_device *
parent_hub = hdev_to_hub(parent_hdev);
/* If we're resetting an active hub, take some special actions */
- if (udev->actconfig &&
+ if (udev->actconfig && udev->actconfig->desc.bNumInterfaces > 0 &&
udev->actconfig->interface[0]->dev.driver ==
&hub_driver.driver &&
(hub = hdev_to_hub(udev)) != NULL) {
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