diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index daac0427bfd5..fc235b02ff27 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1606,7 +1606,6 @@ int usb_hcd_check_bandwidth(struct usb_device *udev, struct usb_interface *new_intf) { int num_intfs, i, j; - struct usb_interface_cache *intf_cache; struct usb_host_interface *alt = NULL; int ret = 0; struct usb_hcd *hcd; @@ -1654,15 +1653,8 @@ int usb_hcd_check_bandwidth(struct usb_device *udev, } } for (i = 0; i < num_intfs; ++i) { - - /* Dig the endpoints for alt setting 0 out of the - * interface cache for this interface - */ - intf_cache = new_config->intf_cache[i]; - for (j = 0; j < intf_cache->num_altsetting; j++) { - if (intf_cache->altsetting[j].desc.bAlternateSetting == 0) - alt = &intf_cache->altsetting[j]; - } + /* Set up endpoints for alternate interface setting 0 */ + alt = usb_find_alt_setting(new_config, i, 0); if (!alt) { printk(KERN_DEBUG "Did not find alt setting 0 for intf %d\n", i); continue; diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index d1e9440799de..99e54586a545 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -63,6 +63,43 @@ MODULE_PARM_DESC(autosuspend, "default autosuspend delay"); #endif +/** + * usb_find_alt_setting() - Given a configuration, find the alternate setting + * for the given interface. + * @config - the configuration to search (not necessarily the current config). + * @iface_num - interface number to search in + * @alt_num - alternate interface setting number to search for. + * + * Search the configuration's interface cache for the given alt setting. + */ +struct usb_host_interface *usb_find_alt_setting( + struct usb_host_config *config, + unsigned int iface_num, + unsigned int alt_num) +{ + struct usb_interface_cache *intf_cache = NULL; + int i; + + for (i = 0; i < config->desc.bNumInterfaces; i++) { + if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber + == iface_num) { + intf_cache = config->intf_cache[i]; + break; + } + } + if (!intf_cache) + return NULL; + for (i = 0; i < intf_cache->num_altsetting; i++) + if (intf_cache->altsetting[i].desc.bAlternateSetting == alt_num) + return &intf_cache->altsetting[i]; + + printk(KERN_DEBUG "Did not find alt setting %u for intf %u, " + "config %u\n", alt_num, iface_num, + config->desc.bConfigurationValue); + return NULL; +} +EXPORT_SYMBOL_GPL(usb_find_alt_setting); + /** * usb_ifnum_to_if - get the interface object with a given interface number * @dev: the device whose current configuration is considered diff --git a/include/linux/usb.h b/include/linux/usb.h index 6af3581e1114..e101a2d04d75 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -619,6 +619,10 @@ extern struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev, unsigned ifnum); extern struct usb_host_interface *usb_altnum_to_altsetting( const struct usb_interface *intf, unsigned int altnum); +extern struct usb_host_interface *usb_find_alt_setting( + struct usb_host_config *config, + unsigned int iface_num, + unsigned int alt_num); /**