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Update keyboard report descriptor for USB compliance (#21626)

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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.
This commit is contained in:
Stefan Kerkmann 2023-07-28 02:05:01 +02:00 • committed by GitHub
parent 3a413e4bad
commit 32174abcfa
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tmk_core/protocol/vusb/vusb.c
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@ -435,6 +435,8 @@ const PROGMEM uchar keyboard_hid_report[] = {
0x05, 0x08, // Usage Page (LED)
0x19, 0x01, // Usage Minimum (Num Lock)
0x29, 0x05, // Usage Maximum (Kana)
0x15, 0x00, // Logical Minimum (0)
0x25, 0x01, // Logical Maximum (1)
0x95, 0x05, // Report Count (5)
0x75, 0x01, // Report Size (1)
0x91, 0x02, // Output (Data, Variable, Absolute)