Re: [PATCH] Revert "usb: gadget: composite: fix OS descriptors w_value

[Greg KH <greg@kroah.com>]

On Fri, Sep 13, 2024 at 05:39:21PM +0200, Peter Korsgaard wrote:
> On 9/11/24 03:32, Vodicka, Michal wrote:
> > > Hmm, very odd. How are you testing this on the host side?
> > 
> > We just attach the device and check the registry values created by OS
> > for our device. As
> > HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB\VID_XXXX&PID_YYYY&MI_NN\<device_instance>\Device Parameters.
> > When it works our extended properties are created there.
> > 
> > We check the communication using USB analyzer which clearly shows
> > wValue bytes are in opposite order than documented. This is SETUP
> > packet captured:
> > 
> > Offset  0   1   2   3   4   5   6   7
> > 0x000   C1  A1  02  00  05  00  0A  00
> > 
> > As you can see, this is interface request and out interface number was
> > 2 which is in the low byte of wValue.
> 
> OK, annoying. I am traveling for conferences this/next week so I cannot
> verify here, but presumably you are correct. Do you perhaps have a more
> complete capture you can share?
> 
> 
> > 
> > > Could it be that you are running into the WinUSB bug described here:
> > 
> > No. The mentioned bug is in wIndex and out problem is wValue. Also,
> > MSOS descriptors are read before WinUsb is even run.
> 
> Ahh yes, indeed.
> 
> 
> > What Windows version were you using and have you used USB analyzer to
> > check the communication?
> 
> It's been a while, but I believe Windows 10. In the end I ended up shuffling
> the interfaces around so the one with the MSOS descriptors was interface 0
> for better compatibility, so it is possible that something went wrong with
> my interface != 0 tests.
> 
> If so, then I am fine with reverting, but we should probably add a comment
> explaining that the documentation is wrong.

Ok, Michal, can you add some text tothe changelog and send a v2 for
this?

thanks,

greg k-h