Re: [PATCH] USB: Gadget: g_multi: added INF file for gadget withmultiple configurations

From: Xiaofan Chen
Date: Fri Aug 13 2010 - 21:28:27 EST


On Sat, Aug 14, 2010 at 4:35 AM, Michal Nazarewicz <mina86@xxxxxxxxxx> wrote:
> Xiaofan Chen <xiaofanc@xxxxxxxxx> writes:
>
>> On Fri, Aug 13, 2010 at 5:31 PM, Dries Van Puymbroeck
>> <dries.van.puymbroeck@xxxxxxxxx> wrote:
>>> When a mutlifunction gadget has more than 1 configuration, Windows does not
>>> use its generic driver for multifunctional USB devices.
>>
>> Sorry but what do you mean by the above?
>> As per the previous discussions, it seems that a registry entry hack
>> (for Vista and Windows 7) is needed.
>> http://msdn.microsoft.com/en-us/library/ff538059%28VS.85%29.aspx
>>
>>> This commit adds an INF file that will load the required Windows driver
>>> as well as a short description in gadget_multi.txt
>>
>> It seems to me your inf file forces the USB Generic
>> Parent Driver (for USB Composite Device) to load. But for which
>> configuration? I do not have any device to test myself. But
>> I tend to guess it will still be the first configuration (either
>> RNDIS or CDC ECM).
>
> 2-configuration g_multi has configuration with RNDIS as the first one so
> that's pretty perfect for us.

I guess so. But I am wondering if the inf file really needed or not
in this case.

Basically I am just wondering if the following statement is true or not.
>>> When a mutlifunction gadget has more than 1 configuration, Windows does not
>>> use its generic driver for multifunction USB devices.

I am thinking the inf file is not necessary.
"When the system detects that a USB device is composite, it loads the
USB common class generic parent driver (usbccgp.sys)."
http://msdn.microsoft.com/en-us/library/ff538059%28VS.85%29.aspx

And since 1st configuration RNDIS is what desired, nothing needs to be done.

Obviously you have the device to test, I would be interested to know your
test results under XP, Vista and Win7.

--
Xiaofan
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