Handle HID OUT reports with no report ID

[dhalbert]

Raw HID OUT reports (to the peripheral from the host), with no report ID, were not being parsed correctly. The code assumed the first byte was the report id. However, this is not always the case.

Instead, see if there is a defined HID device with report ID 0, whose report length matches the incoming report. If so, assume the incoming report is for that device.

The long-term fix is for TinyUSB to know which reports are for which report ID's, but that requires hathach/tinyusb#1095 to be addressed.

Tested with hidapitester on Linux:

sudo /home/halbert/bin/hidapitester --vidpid 239a/80f2 --open --length 64 --send-output 7,8,9
Opening device, vid/pid: 0x239A/0x80F2
Writing output report of 64-bytes...wrote 64 bytes:
 07 08 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Closing device

On the CPy side:

>>> import rawread
None
None
None
b'\x07\x08\t\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
None

test program (rawread.py):

import usb_hid
import time

d = usb_hid.devices[0]

while True:
    print(d.get_last_received_report())
    time.sleep(2)

boot.py:

import usb_hid

RAWHID_REPORT_DESCRIPTOR = bytes((
    0x06, 0x00, 0xFF,  # Usage Page (Vendor Defined 0xFF00)
    0x09, 0x01,        # Usage (0x01)
    0xA1, 0x01,        # Collection (Application)
    0x09, 0x02,        #   Usage (0x02)
    0x15, 0x00,        #   Logical Minimum (0)
    0x26, 0xFF, 0x00,  #   Logical Maximum (255)
    0x75, 0x08,        #   Report Size (8)
    0x95, 0x40,        #   Report Count (64)
    0x81, 0x02,        #   Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
    0x09, 0x03,        #   Usage (0x03)
    0x15, 0x00,        #   Logical Minimum (0)
    0x26, 0xFF, 0x00,  #   Logical Maximum (255)
    0x75, 0x08,        #   Report Size (8)
    0x95, 0x40,        #   Report Count (64)
    0x91, 0x02,        #   Output (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
    0xC0,              # End Collection
))

raw_hid = usb_hid.Device(
    report_descriptor=RAWHID_REPORT_DESCRIPTOR,
    usage_page=0xFF00,
    usage=0x01,
    report_ids=(0,),
    in_report_lengths=(64,),
    out_report_lengths=(64,),
)

usb_hid.enable((raw_hid,))
#usb_hid.enable((usb_hid.Device.KEYBOARD,))

[dhalbert]

I also tested existing support for OUT reports, using Keyboard, and sending Keycode.CAPS_LOCK, and I see the Keyboard.led_status still changing as it should.

[tannewt]

Looks good to me! Thank you!

[dhalbert]

@tannewt I managed to get the builds to fit by casting some more optimizer spells.

[jepler]

Thanks