On Mon, Jun 15, 2020 at 01:46:08AM -0700, Andrew P. Lentvorski wrote: > I've got a bulk transport kernel module composite function. Nothing > fancy, just opens the two pipes to a character device just like f_hid.c. > It works fine, as far as I can tell. > > Now, I'm trying to implement WCID so that Windows will automatically > recognize it and attach it to the WinUSB drivers. > > However, I simply cannot figure out how to create a string with an index > of 0xEE and data of "MSFT100" so that Windows will pick up the device > and then request the extra features. > > Alternatively, I'm happy to adjust my bcdUSB to flag USB 2.01 or USB 2.1 > and use the BOS system. However, as there appear to be very few > examples of that in the Linux codebase (none that I can see--but I'm not > on latest), I suspect that would be just swapping something that might > be possible but I'm just missing the path vs something that has a path > that is wholly untrod. > > WCID References: > https://github.com/pbatard/libwdi/wiki/WCID-Devices > https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors > > Any help, advice or pointers would be appreciated. While I'm certainly not an expert in this area, here's a suggestion: Look through the .h and .c files for the composite framework, searching for things related to use_os_string, b_vendor_code, bMS_VendorCode, and so on. The subject is a little tricky, because the composite framework is all about building a single gadget driver from multiple function drivers. A gadget can have only one string descriptor with index 0xEE (ignoring language issues), so somehow the requirements of the various function drivers have to be reconciled. Alan Stern
