Re: [PATCH] HID: usbhid: add HID_QUIRK_SKIP_FEATURE_REPORT_ID

[Fedor Gubenkov]

Please drop this patch; I'm NAK-ing my own submission.

After further testing against the actual device, the premise of this
patch is wrong. The dongle (3689:8762) *requires* the report ID byte in
the SET_REPORT(Feature) payload. Captured at the USB level:

  - SET_REPORT(Feature) with the report ID present (21 bytes): the device
    returns a valid, challenge-dependent response.
  - SET_REPORT(Feature) with the report ID stripped (20 bytes) - exactly
    what HID_QUIRK_SKIP_FEATURE_REPORT_ID produces - the device returns a
    single constant byte (0xe7) for every challenge, i.e. an invalid
    reply.

So the unmodified usbhid behaviour (report ID included, as mandated by
the HID spec for numbered reports) is already correct for this device,
and the quirk breaks the only device it targets. My earlier "the 20-byte
transfer works" observation was a flawed comparison that used a different
challenge and never actually elicited a valid response.

Sorry for the noise.

Thanks,
Fedor