Hi, I suggest some changes in the USB HID support of the Linux Gadget kernel framework. The problem is that several Keyboard and Mouse implementations using this framework are in fact fully compatible with BOOT mode. They announce in the descriptor as "Boot Interface Subclass", but they don't work with BIOSes, KVMs and other simple USB implementations because the lack of Get_Protocol() & Set_Protocol() functions. Here the info about the specifications: - Documentation about USB HID Interfaces: http://www.usb.org/developers/hidpage/HID1_11.pdf - Page 73, Appendix F: Legacy Keyboard Implementation: Any boot device can work as Legacy if it can change to BOOT mode. So, this assumes that when the device is initialized it isn't in the boot mode, but in the report mode. - Page 78, Appendix G: HID Request Support Requirements: If the Report Descriptor of the device is fully compatible with the BOOT mode, then the only remaining requirement is the implementation of the Get_Protocol and Set_Protocol functions. - Page 54: 7.2.5 Get_Protocol Request / 7.2.6 Set_Protocol Request The correct implementation of these functions are change the status and report the status, that is a binary value (0=Boot Protocol, 1=Report Protocol). Problem: These functions are miss unimplemented in the kernel... See file "/drivers/usb/gadget/function/f_hid.c" http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/ drivers/usb/gadget/function/f_hid.c?id=refs/tags/v4.1-rc3 Inside the function: "static int hidg_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)" the call to set_protocol and get_protocol raises "stall" returning NON_SUPPORTED. Then the solution for solving this problem is always change from Report to Boot, and viceversa. Implementing a binary value returned by get_protocol (at initialization the correct value is "1"=Report mode). I suggest that someone responsible of this framework implement this change. I feel it be easy to do, and I hope s/he can do it soon. Best. -- 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
