On Thu, Jul 22, 2010 at 9:01 AM, Xiaofan Chen <xiaofanc@xxxxxxxxx> wrote: > 2010/7/22 Adam Kropelin <akropel1@xxxxxxxxxxxxxxxx>: >>> Windows would still choose the first configuration so all would be grand. >> >> Actually, Windows' enumeration of composite devices is quite broken >> (ok, maybe "not ideal") and it will in fact only select a >> configuration if a composite device has a single config. > > Just for the reference. > http://blogs.msdn.com/b/usbcoreblog/archive/2010/05/19/multi-config-usb-devices-and-windows.aspx > http://msdn.microsoft.com/en-us/library/ff538059%28VS.85%29.aspx Yes, exactly. > From what I read, I think you are right. And it seems to me that it is not > a very good idea to have a USB Composite device with multiple > configurations. What is the use case for that? I don't know. My device has only a single config into which it places several interfaces grouped by IADs. I had expected Linux to simply ignore the RNDIS interfaces if couldn't utilize them, but instead it refuses to select the config at all, rendering the other interfaces inaccessible. When I attempted to work around the issue by providing a second fallback config to satisfy Linux, Windows broke due to the issue outlined in that blog post. Catch 22. --Adam -- 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
