From 91017f9cf5fcfb601b8d583c896ac7de7d200c57 Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Thu, 3 Dec 2009 09:44:34 -0800 Subject: [PATCH] USB: Refactor code to find alternate interface settings. Refactor out the code to find alternate interface settings into usb_find_alt_setting(). Print a debugging message and return null if the alt setting is not found. While we're at it, correct a bug in the refactored code. The interfaces in the configuration's interface cache are not necessarily in numerical order, so we can't just use the interface number as an array index. Loop through the interface caches, looking for the correct interface. Signed-off-by: Sarah Sharp Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hcd.c | 12 ++---------- drivers/usb/core/usb.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/usb.h | 4 ++++ 3 files changed, 43 insertions(+), 10 deletions(-) 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); /** -- 2.20.1