On Wed, Mar 25, 2015 at 12:12 PM, Andrew Silverman <andre...@microsoft.com> wrote: > What I don't really understand is the 0x43/0xC3 bytes for requesttype > and the E9/EA/EB values in request. (Assuming that I am correctly > understanding > those param mappings in the existing calls to usb_control_msg, anyway.) > I can't seem to find anything in the description of USB control messages that > makes those values make sense.
The requests from 0x40 to 0x43 (and 0x80 to 0x83) are specifically defined as "vendor" messages, where the vendor can assign any meaning they want. So you have to carry out reverse engineering to try to understand. Ref: USB 2.0 Specification Chapter 9. http://www.usb.org/developers/docs/usb20_docs/ 9.3 USB Device Requests All USB devices respond to requests from the host on the device’s Default Control Pipe. These requests are made using control transfers. The request and the request’s parameters are sent to the device in the Setup packet. The host is responsible for establishing the values passed in the fields listed in Table 9-2. EverySetup packet has eight bytes. Table 9-2. Format of Setup Data Offset: 0 Field: bmRequestType Size: 1 Value: Bitmap Characteristics of request: D7: Data transfer direction 0 = Host-to-device 1 = Device-to-host D6...5: Type 0 = Standard 1 = Class 2 = Vendor 3 = Reserved D4...0: Recipient 0 = Device 1 = Interface 2 = Endpoint 3 = Other 4...31 = Reserved -- Xiaofan _______________________________________________ libhid-discuss mailing list libhid-discuss@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/libhid-discuss http://libhid.alioth.debian.org/