Thanks for your reply, Krzysztof. I now understand all the fields. However, I just realize I can't really extend your example to cover my need, because your example uses RNDIS where kernel already support OS descriptor. In my case I'm preparing my own functionfs-based gadget. I suppose somewhere inside my functionfs daemon, I should add OS descriptor support. Is that understanding right? If so, is there any example? I searched around internet and can't seem to find a single example where functionfs-based USB gadget supports OS descriptor. In fact, it is not even clear to me what kernel interfaces are used for conveying OS descriptor for functionfs-based function. Thanks again. Really appreciate your help. Jun On Wed, Feb 7, 2018 at 1:30 AM, Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx> wrote: > > > On 02/07/2018 08:25 AM, Jun Sun wrote: >> >> Thanks, Krysztof. >> >> I'm trying to follow your example and maybe to massage it into my need. >> >> One quick question - >> >> In your example, you set vendor code to be 0xBC. Is this code of any >> significance? What values should I use? >> >> b_vendor_code = 0xBC, > > > Well... according to "spec"[1]: > > "bMS_VendorCode is used to retrieve the associated feature descriptors. The > vendor defines the format of this field. For further details, see “OS > Feature Descriptors” later in this paper." > > USB complete[2] elaborates this pretty good. But to be totally honest I took > this value from 3. > > So from your perspective this could be any value other than 0;) > > Footnotes: > 1 - > https://docs.microsoft.com/en-us/windows-hardware/drivers/network/mb-interface-model-supplement > > 2 - > https://books.google.pl/books?id=pkefBgAAQBAJ&pg=PA347&lpg=PA347&dq=bMS_VendorCode+rndis&source=bl&ots=6_hwlTDvwy&sig=WmjSiXX9qvWF5aLBxa8M7xYvDNM&hl=pl&sa=X&ved=0ahUKEwj1kcXzvJPZAhVK16QKHeVuAOMQ6AEIRDAE#v=onepage&q=bMS_VendorCode%20rndis&f=false > > 3 - http://doc.hcc-embedded.com/download/attachments/27590911/HCC RNDIS > Device Class Driver Windows Automatic Installation Guide > v1.10.pdf?version=1&modificationDate=1507279811000&api=v2 > > > Best regards, > -- > Krzysztof Opasiak > Samsung R&D Institute Poland > Samsung Electronics -- 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
