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Questions tagged [udev]

Udev manages the Linux /dev directory, and hooks userspace into kernel device events.

udev (userspace /dev) is a device manager for the Linux kernel. As the successor of devfsd and hotplug, udev primarily manages device nodes in the /dev directory. At the same time, udev also handles all user space events raised when hardware devices are added into the system or removed from it, including firmware loading as required by certain devices.

https://en.wikipedia.org/wiki/Udev

https://wiki.debian.org/udev

http://reactivated.net/writing_udev_rules.html

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How to get host's udev events from a Docker container?

In a Docker container, I am looking for a way to get the udev events on the host. Using udevadm monitor, it sends back host's kernel events only in a container. The question is whether there is a way to detect host's udev events or forward host's…
ichbinblau
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udev rule works in `udevadm test`, but not `udevadm trigger`

I have a udev rule for a 4-port USB-to-RS232 hub, created based on this question: SUBSYSTEMS=="usb", DRIVERS=="usb", ATTRS{serial}=="A4018BU0", SYMLINK+="ttyLumagen" It does not create the symlink as expected, so to debug I tried udevadm test and it…
ScottJ
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ubuntu 12.04 libudev-dev won't install because of dependencies

I have a some sample c++ code that receives hotplug events using the udev library. It worked fine in Ubuntu 10.04. It's only prerequisite was the libudev-dev package: sudo apt-get install libudev-dev But when I tried to install that package in…
JohnA
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Need more than 32 USB sound cards on my system

I'm working on an educative multiseat project where we need to connect 36 keyboards and 36 USB sound cards to a single computer. We're running Ubuntu Linux 12.04 with the 3.6.3-030603-generic kernel. So far we've managed to get the input from the 36…
picheto
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add udev rule for external display

I wrote a small shell script configuring attached external displays with xrandr. # cat /home/didi/bin/monitor_autoswitcher.sh #!/bin/bash xrandr | grep "HDMI1 connected" if [[ $? == 0 ]]; then # is connected xrandr --output HDMI1 --right-of…
didi_X8
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udev: device connected at boot time

I'm using udev to detect USB drive connection and disconnection on my Ubuntu 10.04 LTS x64 server. Everything works fine when USB devices are connected while the machine is running, but if one is already present at boot time, my script does not…
Bob Sammers
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Docker Linux Mint NetworkManager failed to find device with udev

Using: Linux 4.13.0-26-generic #29~16.04.2-Ubuntu SMP Tue Jan 9 22:00:44 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux I've been noticing my system hesitating while working, and finally tracked it down to something wonky going on with Docker veth…
Mike Crowe
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Udev rule with ACTION=="add" not being triggered when device is already connected at boot

Here is my simple udev rule: ACTION=="add",SUBSYSTEM=="usb",DEVPATH=="/devices/pci0000:00/0000:00:14.0/usb3/3-13",RUN+="/opt/usb-libvirt-hotplug/usb-libvirt-hotplug.sh…
Vain
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How does polling a file for changes work?

The problem I expected the script below to print at most one event and then stop (it's written only to illustrate the problem). #!/usr/bin/env python from select import poll, POLLIN filename = "test.tmp" # make sure file exists open(filename,…
Lauritz V. Thaulow
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udevadm does not show all attributes inside a docker container

When I run docker container and list properties of some device with udevadm inside the container, there are only the basic information about the device. When I do the same thing on host, I can see much more. What can I do to get all the information…
pallly
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Why don't my udev rules work inside of a running docker container?

I have udev rules written to create SYMLINKS when a device is connected. The rules are working fine on the host machine, but when I start a container with these same rules installed in /etc/udev/rules.d, they don't work inside my container. I am…
Ryan
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ftdi d2xx conflict with ftdi_sio on linux - How to remove ftdi_sio automatically

I have a rf-reader with ftdio usb to serial chip. I was able to write a program to control it using ftdi d2xx library. So far so good. The issue is that when the reader is reconnected to the PC I have to remove ftdi_sio and usbserial mods using this…
Amin Y
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udev not capturing information (lot of missing attributes) for usb device

I have two systems, one running Ubutu 14.04, one running raspbian. When I connect a usb printer to my Ubuntu machine I can can get lots of information about from udevadm: :~$ udevadm info -q property --export -n /dev/usb/lp2 …
preston.m.price
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udev rule with few parent device attributes

I need complex and universal udev rule to determine USB-device plugged in certain port of the any USB hub. so, i have to combine parent attributes of different layers of the device tree... I have this: $udevadm info --query=all --name=/dev/ttyUSB0…
EDkan
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The difference between vold and udevd

I knew that Android uses volume daemon instead of udevd. Since both of these two daemons act similar as the following: Use netlink socket to receive uevents sent from kernel. Deals with file nodes for further processing. I am not clear with the…
Sam
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