2010/9/2 Michał Nazarewicz <m.nazarewicz@xxxxxxxxxxx>: > On Thu, 02 Sep 2010 00:32:51 +0200, David Brownell <david-b@xxxxxxxxxxx> > wrote: >> >> Seems buglike to me. Almost as buglike as even >> wanting an IAD given a CDC Union descriptor. > > Windows failed to correctly detect composite functions in a composite > gadget if IAD's were missing. > > Ideally, a patch that adds IAD only for composite gadget (ie. gadget with > many composite functions) would be perfect. > More details: When an CDC-ACM device is involved in a USB composite device, you need to use IAD (interface association descriptor). Moreover, you need to use XP SP3 or Vista SP 1 (or later) or Windows 7. If you are using XP SP2, then you need two hotfixes. More information: http://www.microchip.com/forums/fb.ashx?m=268852 (archive of Jan Axelson's orginal post in usb.org forum) An example: http://www.cygnal.org/ubb/Forum9/HTML/001050.html Faq from Jan Axelson. ************ http://www.lvr.com/serport.htm "To create a composite USB device that contains a CDC function, use an interface association descriptor to specify the CDC interfaces. Windows XP also requires the two hotfixes described in these articles: The Usbser.sys driver may not load when a USB device uses an IAD. Microsoft Knowledge Base article ID 918365. Updates usbser.sys to version 5.1.2600.2930. A Tablet PC that is running Windows XP Tablet PC Edition 2005 stops responding (hangs) when you put it into standby or into hibernation. Microsoft Knowledge Base article ID KB935892. Updates usbccgp.sys to version 5.1.2600.3116. ************ Take note the above two hot fixes are included in XP SP3. May comment in f_acm.c refers to 'The new "association" descriptors'. The better name is "interface association descriptor" or IAD. -- Xiaofan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
