I have read lot of research about this and I am still struggling to configure a usbtmc device using udev rules. I am running my test on Raspberry Pi OS 5.15.
My udev rules /etc/udev/rules.d/99-usbtmc.rules are :
SUBSYSTEMS=="usb", ACTION=="add", ATTRS{idVendor}=="F4EC", ATTRS{idProduct}=="EE3A", GROUP="usbtmc", MODE="0660"
The permissions of the device are wrong :
$ ls -l /dev/usbtmc0
crw------- 1 root root 180, 176 Nov 7 17:38 /dev/usbtmc0
Here is the output of udevadm info:
$ udevadm info -a /dev/usbtmc0
Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.
looking at device '/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1/1-1.1/1-1.1:1.0/usbmisc/usbtmc0':
KERNEL=="usbtmc0"
SUBSYSTEM=="usbmisc"
DRIVER==""
ATTR{power/control}=="auto"
ATTR{power/runtime_active_time}=="0"
ATTR{power/runtime_status}=="unsupported"
ATTR{power/runtime_suspended_time}=="0"
looking at parent device '/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1/1-1.1/1-1.1:1.0':
KERNELS=="1-1.1:1.0"
SUBSYSTEMS=="usb"
DRIVERS=="usbtmc"
ATTRS{authorized}=="1"
ATTRS{bAlternateSetting}==" 0"
ATTRS{bInterfaceClass}=="fe"
ATTRS{bInterfaceNumber}=="00"
ATTRS{bInterfaceProtocol}=="01"
ATTRS{bInterfaceSubClass}=="03"
ATTRS{bNumEndpoints}=="03"
ATTRS{device_capabilities}=="0"
ATTRS{interface_capabilities}=="0"
ATTRS{supports_autosuspend}=="0"
ATTRS{usb488_device_capabilities}=="15"
ATTRS{usb488_interface_capabilities}=="7"
looking at parent device '/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1/1-1.1':
KERNELS=="1-1.1"
SUBSYSTEMS=="usb"
DRIVERS=="usb"
ATTRS{authorized}=="1"
ATTRS{avoid_reset_quirk}=="0"
ATTRS{bConfigurationValue}=="1"
ATTRS{bDeviceClass}=="00"
ATTRS{bDeviceProtocol}=="00"
ATTRS{bDeviceSubClass}=="00"
ATTRS{bMaxPacketSize0}=="64"
ATTRS{bMaxPower}=="2mA"
ATTRS{bNumConfigurations}=="1"
ATTRS{bNumInterfaces}==" 1"
ATTRS{bcdDevice}=="0200"
ATTRS{bmAttributes}=="c0"
ATTRS{busnum}=="1"
ATTRS{configuration}==""
ATTRS{devnum}=="3"
ATTRS{devpath}=="1.1"
ATTRS{devspec}=="(null)"
ATTRS{idProduct}=="ee3a"
ATTRS{idVendor}=="f4ec"
ATTRS{ltm_capable}=="no"
ATTRS{manufacturer}=="Siglent Technologies Co,. Ltd."
ATTRS{maxchild}=="0"
ATTRS{power/active_duration}=="803000"
ATTRS{power/autosuspend}=="2"
ATTRS{power/autosuspend_delay_ms}=="2000"
ATTRS{power/connected_duration}=="803000"
ATTRS{power/control}=="on"
ATTRS{power/level}=="on"
ATTRS{power/persist}=="1"
ATTRS{power/runtime_active_time}=="802770"
ATTRS{power/runtime_status}=="active"
ATTRS{power/runtime_suspended_time}=="0"
ATTRS{product}=="2569-MSO"
ATTRS{quirks}=="0x0"
ATTRS{removable}=="unknown"
ATTRS{rx_lanes}=="1"
ATTRS{serial}=="499A20103"
ATTRS{speed}=="12"
ATTRS{tx_lanes}=="1"
ATTRS{urbnum}=="30"
ATTRS{version}==" 2.00"
looking at parent device '/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1':
KERNELS=="1-1"
SUBSYSTEMS=="usb"
DRIVERS=="usb"
ATTRS{authorized}=="1"
ATTRS{avoid_reset_quirk}=="0"
ATTRS{bConfigurationValue}=="1"
ATTRS{bDeviceClass}=="09"
ATTRS{bDeviceProtocol}=="01"
ATTRS{bDeviceSubClass}=="00"
ATTRS{bMaxPacketSize0}=="64"
ATTRS{bMaxPower}=="100mA"
ATTRS{bNumConfigurations}=="1"
ATTRS{bNumInterfaces}==" 1"
ATTRS{bcdDevice}=="0421"
ATTRS{bmAttributes}=="e0"
ATTRS{busnum}=="1"
ATTRS{configuration}==""
ATTRS{devnum}=="2"
ATTRS{devpath}=="1"
ATTRS{devspec}=="(null)"
ATTRS{idProduct}=="3431"
ATTRS{idVendor}=="2109"
ATTRS{ltm_capable}=="no"
ATTRS{maxchild}=="4"
ATTRS{power/active_duration}=="803590"
ATTRS{power/autosuspend}=="0"
ATTRS{power/autosuspend_delay_ms}=="0"
ATTRS{power/connected_duration}=="803590"
ATTRS{power/control}=="auto"
ATTRS{power/level}=="auto"
ATTRS{power/runtime_active_time}=="803254"
ATTRS{power/runtime_status}=="active"
ATTRS{power/runtime_suspended_time}=="0"
ATTRS{product}=="USB2.0 Hub"
ATTRS{quirks}=="0x0"
ATTRS{removable}=="unknown"
ATTRS{rx_lanes}=="1"
ATTRS{speed}=="480"
ATTRS{tx_lanes}=="1"
ATTRS{urbnum}=="1165"
ATTRS{version}==" 2.10"
looking at parent device '/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1':
KERNELS=="usb1"
SUBSYSTEMS=="usb"
DRIVERS=="usb"
ATTRS{authorized}=="1"
ATTRS{authorized_default}=="1"
ATTRS{avoid_reset_quirk}=="0"
ATTRS{bConfigurationValue}=="1"
ATTRS{bDeviceClass}=="09"
ATTRS{bDeviceProtocol}=="01"
ATTRS{bDeviceSubClass}=="00"
ATTRS{bMaxPacketSize0}=="64"
ATTRS{bMaxPower}=="0mA"
ATTRS{bNumConfigurations}=="1"
ATTRS{bNumInterfaces}==" 1"
ATTRS{bcdDevice}=="0515"
ATTRS{bmAttributes}=="e0"
ATTRS{busnum}=="1"
ATTRS{configuration}==""
ATTRS{devnum}=="1"
ATTRS{devpath}=="0"
ATTRS{idProduct}=="0002"
ATTRS{idVendor}=="1d6b"
ATTRS{interface_authorized_default}=="1"
ATTRS{ltm_capable}=="no"
ATTRS{manufacturer}=="Linux 5.15.74-v7l+ xhci-hcd"
ATTRS{maxchild}=="1"
ATTRS{power/active_duration}=="803760"
ATTRS{power/autosuspend}=="0"
ATTRS{power/autosuspend_delay_ms}=="0"
ATTRS{power/connected_duration}=="803760"
ATTRS{power/control}=="auto"
ATTRS{power/level}=="auto"
ATTRS{power/runtime_active_time}=="803751"
ATTRS{power/runtime_status}=="active"
ATTRS{power/runtime_suspended_time}=="0"
ATTRS{product}=="xHCI Host Controller"
ATTRS{quirks}=="0x0"
ATTRS{removable}=="unknown"
ATTRS{rx_lanes}=="1"
ATTRS{serial}=="0000:01:00.0"
ATTRS{speed}=="480"
ATTRS{tx_lanes}=="1"
ATTRS{urbnum}=="27"
ATTRS{version}==" 2.00"
looking at parent device '/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0':
KERNELS=="0000:01:00.0"
SUBSYSTEMS=="pci"
DRIVERS=="xhci_hcd"
ATTRS{ari_enabled}=="0"
ATTRS{broken_parity_status}=="0"
ATTRS{class}=="0x0c0330"
ATTRS{consistent_dma_mask_bits}=="64"
ATTRS{current_link_speed}=="5.0 GT/s PCIe"
ATTRS{current_link_width}=="1"
ATTRS{device}=="0x3483"
ATTRS{dma_mask_bits}=="64"
ATTRS{driver_override}=="(null)"
ATTRS{enable}=="1"
ATTRS{irq}=="78"
ATTRS{local_cpulist}=="0-3"
ATTRS{local_cpus}=="f"
ATTRS{max_link_speed}=="5.0 GT/s PCIe"
ATTRS{max_link_width}=="1"
ATTRS{msi_bus}=="1"
ATTRS{msi_irqs/78}=="msi"
ATTRS{power/control}=="on"
ATTRS{power/runtime_active_time}=="803915"
ATTRS{power/runtime_status}=="active"
ATTRS{power/runtime_suspended_time}=="0"
ATTRS{power_state}=="D0"
ATTRS{reset_method}=="pm bus"
ATTRS{revision}=="0x01"
ATTRS{subsystem_device}=="0x3483"
ATTRS{subsystem_vendor}=="0x1106"
ATTRS{vendor}=="0x1106"
looking at parent device '/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0':
KERNELS=="0000:00:00.0"
SUBSYSTEMS=="pci"
DRIVERS=="pcieport"
ATTRS{ari_enabled}=="0"
ATTRS{broken_parity_status}=="0"
ATTRS{class}=="0x060400"
ATTRS{consistent_dma_mask_bits}=="32"
ATTRS{current_link_speed}=="5.0 GT/s PCIe"
ATTRS{current_link_width}=="1"
ATTRS{device}=="0x2711"
ATTRS{dma_mask_bits}=="32"
ATTRS{driver_override}=="(null)"
ATTRS{enable}=="1"
ATTRS{irq}=="77"
ATTRS{local_cpulist}=="0-3"
ATTRS{local_cpus}=="f"
ATTRS{max_link_speed}=="5.0 GT/s PCIe"
ATTRS{max_link_width}=="1"
ATTRS{msi_bus}=="1"
ATTRS{power/control}=="on"
ATTRS{power/runtime_active_time}=="803932"
ATTRS{power/runtime_status}=="active"
ATTRS{power/runtime_suspended_time}=="0"
ATTRS{power_state}=="D0"
ATTRS{revision}=="0x10"
ATTRS{secondary_bus_number}=="1"
ATTRS{subordinate_bus_number}=="1"
ATTRS{subsystem_device}=="0x0000"
ATTRS{subsystem_vendor}=="0x0000"
ATTRS{vendor}=="0x14e4"
looking at parent device '/devices/platform/scb/fd500000.pcie/pci0000:00':
KERNELS=="pci0000:00"
SUBSYSTEMS==""
DRIVERS==""
ATTRS{power/control}=="auto"
ATTRS{power/runtime_active_time}=="0"
ATTRS{power/runtime_status}=="unsupported"
ATTRS{power/runtime_suspended_time}=="0"
looking at parent device '/devices/platform/scb/fd500000.pcie':
KERNELS=="fd500000.pcie"
SUBSYSTEMS=="platform"
DRIVERS=="brcm-pcie"
ATTRS{driver_override}=="(null)"
ATTRS{power/control}=="auto"
ATTRS{power/runtime_active_time}=="0"
ATTRS{power/runtime_status}=="unsupported"
ATTRS{power/runtime_suspended_time}=="0"
looking at parent device '/devices/platform/scb':
KERNELS=="scb"
SUBSYSTEMS=="platform"
DRIVERS=="simple-pm-bus"
ATTRS{driver_override}=="(null)"
ATTRS{power/control}=="auto"
ATTRS{power/runtime_active_time}=="0"
ATTRS{power/runtime_status}=="unsupported"
ATTRS{power/runtime_suspended_time}=="0"
looking at parent device '/devices/platform':
KERNELS=="platform"
SUBSYSTEMS==""
DRIVERS==""
ATTRS{power/control}=="auto"
ATTRS{power/runtime_active_time}=="0"
ATTRS{power/runtime_status}=="unsupported"
ATTRS{power/runtime_suspended_time}=="0"
And finally the output of udevadm test:
$ udevadm test /sys/bus/usb/devices/1-1/1-1.1/1-1.1:1.0/usbmisc/usbtmc0
This program is for debugging only, it does not run any program
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.
Load module index
Skipping empty file: /etc/systemd/network/99-default.link
Skipping empty file: /etc/systemd/network/73-usb-net-by-mac.link
Created link configuration context.
Reading rules file: /usr/lib/udev/rules.d/10-local-rpi.rules
Reading rules file: /usr/lib/udev/rules.d/15-i2c-modprobe.rules
Reading rules file: /usr/lib/udev/rules.d/40-usb_modeswitch.rules
Reading rules file: /usr/lib/udev/rules.d/50-firmware.rules
Reading rules file: /usr/lib/udev/rules.d/50-udev-default.rules
Reading rules file: /usr/lib/udev/rules.d/55-dm.rules
Reading rules file: /usr/lib/udev/rules.d/56-hpmud.rules
Reading rules file: /usr/lib/udev/rules.d/60-autosuspend.rules
Reading rules file: /usr/lib/udev/rules.d/60-block.rules
Reading rules file: /usr/lib/udev/rules.d/60-cdrom_id.rules
Reading rules file: /usr/lib/udev/rules.d/60-crda.rules
Reading rules file: /usr/lib/udev/rules.d/60-drm.rules
Reading rules file: /usr/lib/udev/rules.d/60-evdev.rules
Reading rules file: /usr/lib/udev/rules.d/60-fido-id.rules
Reading rules file: /usr/lib/udev/rules.d/60-flashrom.rules
Reading rules file: /usr/lib/udev/rules.d/60-i2c-tools.rules
Reading rules file: /usr/lib/udev/rules.d/60-input-id.rules
Reading rules file: /usr/lib/udev/rules.d/60-libgphoto2-6.rules
Reading rules file: /usr/lib/udev/rules.d/60-libopenni2-0.rules
Reading rules file: /usr/lib/udev/rules.d/60-libsane1.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-alsa.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-input.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-storage-dm.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-storage-tape.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-storage.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-v4l.rules
Reading rules file: /usr/lib/udev/rules.d/60-rpi.gpio-common.rules
Reading rules file: /usr/lib/udev/rules.d/60-sensor.rules
Reading rules file: /usr/lib/udev/rules.d/60-serial.rules
Reading rules file: /usr/lib/udev/rules.d/60-triggerhappy.rules
Reading rules file: /usr/lib/udev/rules.d/61-gnome-settings-daemon-rfkill.rules
Reading rules file: /usr/lib/udev/rules.d/61-mutter.rules
Reading rules file: /usr/lib/udev/rules.d/64-btrfs.rules
Reading rules file: /usr/lib/udev/rules.d/64-xorg-xkb.rules
Reading rules file: /usr/lib/udev/rules.d/65-libwacom.rules
Reading rules file: /usr/lib/udev/rules.d/69-cd-sensors.rules
Reading rules file: /usr/lib/udev/rules.d/69-libmtp.rules
Reading rules file: /usr/lib/udev/rules.d/70-joystick.rules
Reading rules file: /usr/lib/udev/rules.d/70-microbit.rules
Reading rules file: /usr/lib/udev/rules.d/70-mouse.rules
Reading rules file: /usr/lib/udev/rules.d/70-power-switch.rules
Reading rules file: /usr/lib/udev/rules.d/70-printers.rules
Reading rules file: /usr/lib/udev/rules.d/70-touchpad.rules
Reading rules file: /usr/lib/udev/rules.d/70-uaccess.rules
Reading rules file: /usr/lib/udev/rules.d/71-ipp-usb.rules
Reading rules file: /usr/lib/udev/rules.d/71-seat.rules
Reading rules file: /usr/lib/udev/rules.d/73-seat-late.rules
Reading rules file: /usr/lib/udev/rules.d/73-special-net-names.rules
Reading rules file: /usr/lib/udev/rules.d/75-net-description.rules
Reading rules file: /usr/lib/udev/rules.d/75-probe_mtd.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-broadmobi-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-cinterion-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-dell-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-dlink-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-ericsson-mbm.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-fibocom-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-foxconn-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-haier-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-huawei-net-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-longcheer-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-mtk-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-nokia-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-pcmcia-device-blacklist.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-qdl-device-blacklist.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-quectel-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-sierra.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-simtech-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-telit-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-tplink-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-ublox-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-usb-device-blacklist.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-usb-serial-adapters-greylist.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-x22x-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/77-mm-zte-port-types.rules
Reading rules file: /usr/lib/udev/rules.d/78-sound-card.rules
Reading rules file: /usr/lib/udev/rules.d/80-debian-compat.rules
Reading rules file: /usr/lib/udev/rules.d/80-drivers.rules
Reading rules file: /usr/lib/udev/rules.d/80-ifupdown.rules
Reading rules file: /usr/lib/udev/rules.d/80-iio-sensor-proxy.rules
Reading rules file: /usr/lib/udev/rules.d/80-libinput-device-groups.rules
Reading rules file: /usr/lib/udev/rules.d/80-mm-candidate.rules
Reading rules file: /usr/lib/udev/rules.d/80-net-setup-link.rules
Reading rules file: /usr/lib/udev/rules.d/80-noobs.rules
Reading rules file: /usr/lib/udev/rules.d/80-udisks2.rules
Reading rules file: /usr/lib/udev/rules.d/84-nm-drivers.rules
Reading rules file: /usr/lib/udev/rules.d/85-hwclock.rules
Reading rules file: /usr/lib/udev/rules.d/85-nm-unmanaged.rules
Reading rules file: /usr/lib/udev/rules.d/85-regulatory.rules
Reading rules file: /usr/lib/udev/rules.d/90-alsa-restore.rules
Reading rules file: /usr/lib/udev/rules.d/90-console-setup.rules
Reading rules file: /usr/lib/udev/rules.d/90-libinput-fuzz-override.rules
Reading rules file: /usr/lib/udev/rules.d/90-nm-thunderbolt.rules
Reading rules file: /usr/lib/udev/rules.d/90-pi-bluetooth.rules
Reading rules file: /usr/lib/udev/rules.d/90-pipewire-alsa.rules
Reading rules file: /usr/lib/udev/rules.d/90-pulseaudio.rules
Reading rules file: /usr/lib/udev/rules.d/91-pulseaudio-rpi.rules
Reading rules file: /usr/lib/udev/rules.d/95-cd-devices.rules
Reading rules file: /usr/lib/udev/rules.d/95-dm-notify.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-csr.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-hid.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-hidpp.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-wup.rules
Reading rules file: /usr/lib/udev/rules.d/96-e2scrub.rules
Reading rules file: /usr/lib/udev/rules.d/97-hid2hci.rules
Reading rules file: /etc/udev/rules.d/99-com.rules
Reading rules file: /usr/lib/udev/rules.d/99-libsane1.rules
Reading rules file: /usr/lib/udev/rules.d/99-systemd.rules
Reading rules file: /etc/udev/rules.d/99-usbtmc.rules
DEVPATH=/devices/platform/scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/usb1/1-1/1-1.1/1-1.1:1.0/usbmisc/usbtmc0
DEVNAME=/dev/usbtmc0
MAJOR=180
MINOR=176
ACTION=add
SUBSYSTEM=usbmisc
Unload module index
Unloaded link configuration context.
Can you explain to me why i still get a root group for my device ? Also I don't understand how we know which rules apply for which device.
I found a similar case on ttyUSB here but without good result.
Thank you
