[hidraw] help with debugging the module on Linux 4.4.180+ on Synology DSM 7

From: Radu Cotescu
Date: Thu Sep 01 2022 - 12:43:39 EST


Hello,

Please excuse me if this message would be better suited to a different
list (linux-usb, linux-input ?!).

I would need hidraw available on my Synology device running DSM 7.
Since Synology doesn't provide the module by default, I downloaded the
Linux kernel source files from Synology, compiled the module myself
and installed it (modprobe). If I run modinfo I get the following
output:

sudo modinfo hidraw
filename: /lib/modules/hidraw.ko
license: GPL
depends:
vermagic: 4.4.180+ SMP mod_unload

BTW, I had to manually use module_init / module_exit to have the
module run its hidraw_init function. I have no clue why the __init
macro didn't work in this case (not a C developer).

However, when I plug in a USB device that should be recognised via
hidraw, I only see hiddev listed:

[1022952.762352] usb 1-1: new full-speed USB device number 20 using xhci_hcd
[1022952.906233] usb 1-1: ep 0x81 - rounding interval to 64
microframes, ep desc says 80 microframes
[1022952.916192] usb 1-1: ep 0x1 - rounding interval to 64
microframes, ep desc says 80 microframes
[1022952.926479] drivers/hid/usbhid/hid-core.c: HID probe called for ifnum 0
[1022952.927386] drivers/hid/usbhid/hid-core.c: submitting ctrl urb:
Get_Report wValue=0x0100 wIndex=0x0000 wLength=64
[1022952.928132] Get empty minor:104
[1022952.931914] hid-generic 0003:16D6:0007.0003: hiddev0: USB HID
v1.11 Device [JABLOTRON ALARMS JA-82T PC Interface] on
usb-0000:00:15.0-1/input0

lsusb reports the following:
lsusb -i
|__usb1 1d6b:0002:0404 09 2.00 480MBit/s 0mA 1IF (Linux
4.4.180+ xhci-hcd xHCI Host Controller 0000:00:15.0) hub
|__1-1 16d6:0007:0100 00 2.00 12MBit/s 100mA 1IF
(JABLOTRON ALARMS JA-82T PC Interface 00000000)
1-1:1.0 (IF) 03:00:00 2EPs () usbhid

Obviously no /dev/hidraw* device is created and /sys/class/hidraw is
empty. Any pointers on how I could figure out what's wrong?

Thanks,
Radu