Interface descriptor info (can be multiple per Config):
 
-I:  If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=ssss
-|   |      |      |       |             |      |       |__Driver name
-|   |      |      |       |             |      |          or "(none)"
-|   |      |      |       |             |      |__InterfaceProtocol
-|   |      |      |       |             |__InterfaceSubClass
-|   |      |      |       |__InterfaceClass
-|   |      |      |__NumberOfEndpoints
-|   |      |__AlternateSettingNumber
-|   |__InterfaceNumber
+I:* If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=ssss
+| | |      |      |       |             |      |       |__Driver name
+| | |      |      |       |             |      |          or "(none)"
+| | |      |      |       |             |      |__InterfaceProtocol
+| | |      |      |       |             |__InterfaceSubClass
+| | |      |      |       |__InterfaceClass
+| | |      |      |__NumberOfEndpoints
+| | |      |__AlternateSettingNumber
+| | |__InterfaceNumber
+| |__ "*" indicates the active altsetting (others are " ")
 |__Interface info tag
 
     A given interface may have one or more "alternate" settings.
 on how to do this.)
 
 The Interface lines can be used to determine what driver is
-being used for each device.
+being used for each device, and which altsetting it activated.
 
 The Configuration lines could be used to list maximum power
 (in milliamps) that a system's USB devices are using.
 
   
 static const char *format_iface =
 /* I:  If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=xxxx*/
-  "I:  If#=%2d Alt=%2d #EPs=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x Driver=%s\n";
+  "I:%c If#=%2d Alt=%2d #EPs=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x Driver=%s\n";
 
 static const char *format_endpt =
 /* E:  Ad=xx(s) Atr=xx(ssss) MxPS=dddd Ivl=D?s */
 {
        const struct usb_interface_descriptor *desc = &intfc->altsetting[setno].desc;
        const char *driver_name = "";
+       int active = 0;
 
        if (start > end)
                return start;
        down_read(&usb_bus_type.subsys.rwsem);
-       if (iface)
+       if (iface) {
                driver_name = (iface->dev.driver
                                ? iface->dev.driver->name
                                : "(none)");
+               active = (desc == &iface->cur_altsetting->desc);
+       }
        start += sprintf(start, format_iface,
+                        active ? '*' : ' ',    /* mark active altsetting */
                         desc->bInterfaceNumber,
                         desc->bAlternateSetting,
                         desc->bNumEndpoints,