Running the "HID Tests" suite of the USB 3 Command Verifier (USB3CV)
tool resulted in the following error:
(HID: 3.2.61) The report descriptor returned in response to a
GetDescriptor(Report) must be compliant with the HID specification.
Byte Number: 37h ( 55d)
Data Field: 91 02
Mnemonic: Output
Value: (Variable)
Errors: Error: LOGICAL MAX MUST be bounded by Report Size
The error stems from the fact that logical minimum and maximum are
global items, which means that the next item in a report descriptor
inherits the value from the previously set value. In this case the
status leds item inherited the logical minimum (=0) and maximum (=255)
from the keycodes item. As the status leds set a report size of 1 bit,
wich can only hold a boolean, it becomes clear that this range would
never fit.
The fix is straightforward, we just define a appropriate logical maximum
(=1), the mismatch is solved and our keyboard now passes the compliance
tests. Defining the logical minimum is redundant in this case but is
kept to form a logical block.
32174abcfa