confused about udevadm usage

Question

The ultimate goal here is to turn on/off touchpad on mouse plug, so I'm trying to get some property of my mouse and my touchpad from udev database, using udevadm but I don't get how this working and unfortunately the manpage isn't clear enough to me…

$ lsb_release -irc
Distributor ID: Debian
Release:    8.4
Codename:   jessie

Here is the kind of information I'm looking for :

KERNEL=="input16"
    SUBSYSTEM=="input"
    DRIVER==""
    ATTR{name}=="Bluetooth Laser Travel Mouse"
    ATTR{phys}=="5c:e0:c5:9d:63:fd"
    ATTR{uniq}=="00:07:61:ec:be:5c"
    ATTR{properties}=="0"

From here I have tried this :

$ udevadm info -a /sys/devices/pci0000\:00/0000\:00\:1c.3/0000\:03\:00.0/usb2/2-1/2-1\:1.0/0003\:1EA7\:0064.0002/input/input25/mouse1/`

and i'm getting this

Unknown device, absolute path in /dev/ or /sys expected.

If I monitor, I get this result:

$ udevadm monitor -k -s input
monitor will print the received events for:
KERNEL - the kernel uevent

KERNEL[4375.486738] remove   /devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0002/input/input25/mouse1 (input)
KERNEL[4375.496500] remove   /devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0002/input/input25/event11 (input)
KERNEL[4375.532441] remove   /devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0002/input/input25 (input)
KERNEL[4377.840574] add      /devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0003/input/input26 (input)
KERNEL[4377.840667] add      /devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0003/input/input26/mouse1 (input)
KERNEL[4377.840759] add      /devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0003/input/input26/event11 (input)

So I have also tried this:

$ udevadm info -a -p /sys/devices/pci0000\:00/0000\:00\:1c.3/0000\:03\:00.0/usb2/2-1/2-1\:1.0/0003\:1EA7\:0064.0002/input/input25/

and this

$ udevadm info -a -p /devices/pci0000\:00/0000\:00\:1c.3/0000\:03\:00.0/usb2/2-1/2-1\:1.0/0003\:1EA7\:0064.0002/input/input25/

and get this result

syspath not found

The only way I manage to get some property is using this command:

$ udevadm info --query=all --name=/dev/input/mouse1

And I get this but, I don't have the attribute I'm looking for…(ie ATTR{name})

P: /devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0003/input/input26/mouse1 
N: input/mouse1 S: input/by-id/usb-1ea7_2.4G_Wireless_Mouse-mouse 
S: input/by-path/pci-0000:03:00.0-usb-0:1:1.0-mouse 
E: DEVLINKS=/dev/input/by-id/usb-1ea7_2.4G_Wireless_Mouse-mouse /dev/input/by-path/pci-0000:03:00.0-usb-0:1:1.0-mouse 
E: DEVNAME=/dev/input/mouse1 
E: DEVPATH=/devices/pci0000:00/0000:00:1c.3/0000:03:00.0/usb2/2-1/2-1:1.0/0003:1EA7:0064.0003/input/input26/mouse1 
E: ID_BUS=usb 
E: ID_INPUT=1 
E: ID_INPUT_MOUSE=1 
E: ID_MODEL=2.4G_Wireless_Mouse 
E: ID_MODEL_ENC=2.4G\x20Wireless\x20Mouse 
E: ID_MODEL_ID=0064 
E: ID_PATH=pci-0000:03:00.0-usb-0:1:1.0 
E: ID_PATH_TAG=pci-0000_03_00_0-usb-0_1_1_0 
E: ID_REVISION=0200 
E: ID_SERIAL=1ea7_2.4G_Wireless_Mouse 
E: ID_TYPE=hid 
E: ID_USB_DRIVER=usbhid 
E: ID_USB_INTERFACES=:030102: 
E: ID_USB_INTERFACE_NUM=00 
E: ID_VENDOR=1ea7 
E: ID_VENDOR_ENC=1ea7 
E: ID_VENDOR_ID=1ea7 
E: MAJOR=13 
E: MINOR=33 
E: SUBSYSTEM=input 
E: USEC_INITIALIZED=77840674

So clearly I've a misunderstanding on how to query udev to get the attribute of a device.

Hope I'm clear enough if anyone has an idea where I'm mistaking any input is welcome !

Thanks !

Matth.

Answer 1

Note that the input number changed (from 25, what you tried, to 26, what ), because those are not guaranteed to be constant across boots. Try

udevadm info -q path -n /dev/input/by-id/usb-1ea7_2.4G_Wireless_Mouse-mouse

with the constant by-id symlinkg to get the path in the format udev expects, then something like

 udevadm info -a -p /path/you/just/got

to walk the path and output all attributes along the way (you may need to use parent attributes to identify it).

You can also combine that:

udevadm info -a -p $(udevadm info -q path -n /dev/whatever)

Answer 2

I used

udevadm info -a /dev/hidraw0   

Answer 3

Remove trailing slashes (/) like udevadm info -a -p /sys/class/net/enp0s3 instead of udevadm info -a -p /sys/class/net/enp0s3/