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Questions tagged [devices]

devices refers to questions about the Unix/Linux device special files, normally these are under /dev. Do not use this tag for physical devices (for that use e.g. usb or pci).

237 questions with no upvoted or accepted answers
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systemd-nspawn: how to allow access to all devices?

I'm trying to create a rough equivalent of Docker's --privileged in a systemd container, but I've got no idea how to allow the container to access all of the devices available on the host (without ...
goyozi's user avatar
  • 161
8 votes
1 answer
2k views

How to rename devices for graphical output such as VGA0

On my Laptop the names of my graphical outputs change depending on what chip is activated in the BIOS. This leads to problems in some scripts where outputs such as VGA-0 or LVDS-0 are specified. So I ...
ifschleife's user avatar
7 votes
0 answers
2k views

Bluetooth keyboard not showing up in /dev/input

I've just installed an Apple Wireless keyboard on a Debian system. I used this guide and only console tools — no X on that machine yet. The keyboard works fine. Now I want to remap a right Cmd key ...
ethc's user avatar
  • 171
5 votes
0 answers
5k views

Check if keyboard and mouse are plugged in with only BusyBox installed

Is there a way to detect if a keyboard and a mouse is plugged in (and working) in Linux? This will be embedded in a PXE setup, so I only have Kernel + Modules and Busybox available. Bonus question: ...
user avatar
5 votes
0 answers
4k views

How do I find out the device node corresponding to my device in SuSE 8?

I'm forced to work with a bunch of point-of-sale systems running SuSE 8. They are my client's computers. We are stuck dealing with these old systems until they get to upgrade their whole fleet to SLE ...
Kal's user avatar
  • 753
4 votes
1 answer
1k views

Trying to run linux kernel using QEMU, having trouble with boot process

For a project, I need to be able to run an uncompressed linux kernel. It was recommended to me to try emulating this using QEMU, since that's less involved than booting it straight on the machine. ...
user3705142's user avatar
4 votes
1 answer
815 views

/dev directory; characteristic device files: network_latency, network_throughput

I'm using some networking devices for car to car communication which runs on Linux 3.10.17 OS. With those devices I've to measure the overall network throughput and latency. Inside the /dev directory, ...
Abdullah Al Mamun's user avatar
4 votes
0 answers
397 views

Modem's GPS data is piped to wrong device

I have a SIM7100E modem running on 4.8.0-26-generic which specifies the following devices: /dev/ttyUSB1 : NMEA port for GPS NMEA data output /dev/ttyUSB2 : AT port for AT commands Connecting to ...
embedded_crysis's user avatar
4 votes
1 answer
1k views

How do I check if sound card is in use and, if possible, which process is using it?

I want to know if a program is using my sound card without my knowledge. I thought about building a program that uses low-level device driver code to do the trick, but am now interested in seeing if I ...
moonman239's user avatar
4 votes
0 answers
1k views

How/where are linux device capabilities / bitfields set?

I have a device that has this output in /proc/bus/input/devices: I: Bus=0003 Vendor=05b8 Product=3280 Version=0111 N: Name="PixArt USB Optical Mouse" P: Phys=usb-0000:00:1a.0-1.1/input0 S: ...
theicfire's user avatar
  • 621
4 votes
0 answers
1k views

How to know the event by looking at /dev/input/by-id

I want to access the keyboard device driver. I usually accesses it by looking at /dev/input/by-name but the event provided by it gets changed every time I log in. After searchin on the Net, I found ...
jayesh hathila's user avatar
3 votes
0 answers
160 views

Linux: Are sockets always on device 00:08?

After opening up a socket in a C program, I ran fstat on it and printed out the major and minor device numbers. I got a major number of 0 and a minor number of 8. Looking at the Linux kernel ...
Daniel Walker's user avatar
3 votes
0 answers
2k views

Flash drive detected by lsusb but not by fdisk

I try to format SanDisk Ultra microSDHC UHS-I Card with adapter but it does not appear on fdisk -l. However, it does appear on lsusb as Bus 001 Device 006: ID 1908:0222 GEMBIRD
Aidis's user avatar
  • 131
3 votes
0 answers
3k views

When i plug in usb camera i get 2 devices

When I plug in the camera to Linux then I get 2 devices /dev/video0 and /dev/video1 Why is that happens and is that normal? Odd numbered devices do not work. /dev/v4l/by-path looks like that: ...
Paxmees's user avatar
  • 131
3 votes
0 answers
597 views

Loading a kernel module at run time using "compatible" property of device node in device-tree

If I know the "compatible" property string of a device(from the device tree), can I use it at runtime to load the corresponding kernel driver module? I do not have access to the driver source. I am ...
wishywashy's user avatar
3 votes
0 answers
1k views

Why does md5sum give inconsistent results on device files?

Backing up some USB flash-drives on Lubuntu 16.04.3 LTS. Plug USB drive into laptop. Automounter does its stuff. I remount all partitions as read-only sudo mount -o remount,ro /dev/sdxn Copy USB ...
Lleu Evans's user avatar
3 votes
0 answers
283 views

simultaneous mounts of devpts

I want to create multiple chroot environments, but I faced the issue with mounting devpts Here is STR: > mkdir -p {1,2}/{proc,sys,dev/pts} > mount -v -t sysfs sysfs 1/sys/ > mount -v -...
vbaskoff's user avatar
3 votes
0 answers
2k views

when running `udevadm test`: `no db file to read /run/udev/data/+gpio_sw:PA7: No such file or directory`

I am trying to write an udev rule that matches a GPIO Pin of my Orange Pi (the GPIOs use the gpio-sunxi kernel module). My ultimate goal is to let users who are member of a particular group access ...
Silly Freak's user avatar
3 votes
0 answers
100 views

Enumerate valid values for mknod

I have access to an embedded device which has a bunch of block/char files under /dev. However, this is not a satisfying description of the hardware, because since the firmware is shared with small ...
Lorenzo Pistone's user avatar
3 votes
0 answers
1k views

Why reading from and writing to framebuffer shows no effect ?

I read a very short description of how to make a Screenshot by making use of the file which represents the framebuffer /dev/fb0. in order to write the screen content: cat /dev/fb0 > file in ...
Abdul Al Hazred's user avatar
3 votes
0 answers
137 views

Is there support for flattened device tree in Sparc 32 port of the Linux kernel?

We are trying to write a minimal bootloader for booting the linux kernel on a Sparc V8 processor simulator. From what I understand, the interface between the bootloader and kernel consists of a data ...
Neha Karanjkar's user avatar
3 votes
0 answers
200 views

Bad/strange USB device issue: failed to shutdown/restart

On a fresh Arch Linux installation with Intel i7 processor and an Nvidia graphics card, I noticed during boot log messages related to a usb device filled the screen before it reached the graphical ...
Stephen S.'s user avatar
3 votes
0 answers
784 views

/dev/sda not appearing after secure erase

I decided to wipe my SSD with a secure erase before installing Arch Linux, since the Arch wiki said that it would improve performance. I followed the instructions listed on the wiki, but now when I ...
cheese1756's user avatar
3 votes
1 answer
825 views

Can renaming a network device cause race conditions?

Arch uses predictable network interface names. MATLAB licenses are linked to the MAC address of eth0, so I need to rename one of my devices eth0. In a machines with only one NIC I can just turn off ...
StrongBad's user avatar
  • 5,291
3 votes
0 answers
330 views

How to know when a device is ready

I have firewire mixing console and I wrote an udev rule which calls a script to set up the whole audio chain (alsa -> pulseaudio -> jackd -> firewire) as soon an the console is switched on. Now I ...
Martin Drautzburg's user avatar
3 votes
0 answers
437 views

How to route one video device to multiple programs

I'd like to direct the output of a single capture card (Hauppauge PVR-150) to two programs: VLC (for streaming on LAN) and MythTV for scheduled recording. I think it's possible to do this with the ...
Jon's user avatar
  • 63
2 votes
1 answer
134 views

umount /chrootedpath /dev/pts after several chroot(s): target is busy

I've been doing several chrooted environments in parallel, each in separate folder (when the script with chroot exited I sometimes run another in same folder), and for a while it seemed fine. But now ...
Alex Martian's user avatar
  • 1,055
2 votes
2 answers
59 views

Switch buttons on only the left-handed mouse (input devices)

I've got two Logitech M650 Mice hooked to by Debian 12 Gnome 44 Machine. One is a "Left-Handed" mouse. I would like to swap the buttons on just the left mouse so that I can use my index ...
gavstar's user avatar
  • 21
2 votes
0 answers
532 views

udev inside lxc container

I am running a privileged Debian LXC Container on Proxmox, and then running Docker inside that. I am attempting to run an Xserver in a Docker container with Sunshine to stream to a Moonlight client. I ...
Dennis George's user avatar
2 votes
0 answers
91 views

Can't open dmcrypt drive after integrity error

I'm using dm-integrity on this drive using cryptsetup directly I formatted it with cryptsetup luksFormat --hash sha384 --cipher aes-xts-plain64 --integrity hmac-sha1. After a while I thing some data ...
testin3r's user avatar
2 votes
0 answers
525 views

How to name a device in the device tree?

I have used a device tree overlay file (dtbo) to add a hardware reference over the i2c-2 node to my device tree. This device is an accelerometer that implements an existing driver that can be found ...
Dillon McCardell's user avatar
2 votes
0 answers
429 views

Automatically lock my Linux computer when I walk away from it

I would like to lock my Linux (GNOME) machine after I walk away from it. Ideally, it should be a small Bluetooth tag / card that I carry in my pocket with a proximity sensor. Is there some software ...
martins16321's user avatar
2 votes
0 answers
432 views

Possible reasons for redirection to /dev/null suddenly breaking

I am using a Bash loop to monitor a process that I spawned, and after some time (hours/days) it sometimes produces an "operation not permitted" error trying to redirect output to /dev/null: /...
emike's user avatar
  • 53
2 votes
1 answer
3k views

How to solve failure in plugging external DVD driver in Ubuntu 20.04?

I have bought an external DVD driver but, after plugging (or booting with the unit already plugged) I see the unit listed in the resources of the computer but I cannot access it: If I try to access ...
Gigiux's user avatar
  • 517
2 votes
0 answers
386 views

Writing udev rule for 2 devices on same subsystem and same ATTRS{name}

I'm really new to udev. I've been using Debian with yoga book (with special kernel branch) for half year now. And the maintainer of this kernel (and the debian image) implemented the force feedback ...
TinLethax's user avatar
2 votes
1 answer
871 views

Access to an i2c device used by the kernel, from user space

On my ARM board there's an I2C PMIC used by the kernel: # i2cdetect -r 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- ...
Mark's user avatar
  • 733
2 votes
0 answers
268 views

type string as if it were a keyboard

I have a bunch of unicode symbols in a file and a script to select and copy one of them (dmenuunicode script in this repository which I've forked). But instead pasting them I would like to save one ...
Jouni's user avatar
  • 121
2 votes
0 answers
1k views

USB Keyboard doesn't work until I manually inspect its device file

So I have a USB Keyboard that I built myself which runs the qmk keyboard firmware. I would preface this by saying that it's possible that this is a bug in the keyboard firmware. However, since the ...
evamvid's user avatar
  • 698
2 votes
0 answers
928 views

How to script AT command to modem?

Every time my USB modem (/dev/dlinkModem) gets unplugged it defaults to "radio disabled mode" (AT+CFUN:4). I can easily enough call AT+CFUN:1 through the minicom application console to enable radio ...
wyldcard's user avatar
  • 121
2 votes
0 answers
87 views

Webcam and Desktop composite with v4l2loopback?

Is there anyway to do a composite video setup where the webcam is overlain onto the desktop and output as a video device (simulated webcam)?
Bob R's user avatar
  • 303
2 votes
0 answers
1k views

Is there any standard for naming RS-485 tty devices/device aliases in Linux?

I know, that there are some standards in tty naming. There is ttyUSBx for USB to serial converters, ttySx for RS-232, ttyAMAx on ARM devices, but I can't find anything about conventions in RS-485 ...
Kamil's user avatar
  • 749
2 votes
0 answers
2k views

What is the difference between `/dev/input/event*` and `/dev/input/mouse*` according to mouses?

Suppose my mouse is associated to /dev/.../event1 and /dev/.../mouse1. I was reading the byte streams of those files, and I noticed that event1 gives much more information than mouse1, which ...
Garmekain's user avatar
  • 270
2 votes
0 answers
201 views

Debugging in android chrome as a non-root user

I am trying to debug a website displayed in Google Chrome on an Android device connected to my box via USB. To this end, there is the remote debugging protocol as implemented in the desktop versions ...
Ярослав Рахматуллин's user avatar
2 votes
0 answers
755 views

Accessing I2C slave devices that are specified in Device Tree

I'm trying to communicate with a device over I2C from my BeagleBone Black, and I'm a bit curious as to the device tree's interpretation of I2C. I see that there are a couple of device nodes within ...
T. Wallis's user avatar
  • 133
2 votes
0 answers
1k views

/dev/random entropy on readonly file system

My hostapd works very well on my raspberry Pi3. But if I put root filesystem in readonly, it does not work. I have put some folders like /var/run and /tmp in a ramdisk filesystem. I have seen ...
Bob5421's user avatar
  • 173
2 votes
0 answers
1k views

Remove extra non-working scanners

I tried to add a USB scanner to my system without any luck and now when I start XSane or Image Scan! for Linux I get a list of non-working scanners. How these can be removed? I've tried: # pacman -...
raspi's user avatar
  • 1,386
2 votes
0 answers
1k views

Accessing a serial device from LXC guest

I have a Fedora 26 host running a privileged Ubuntu 16.04 guest in an LXC container. My goal is to connect to a serial device (/dev/ttyACM0) from the LXC guest. I created the guest OS with the ...
Warren R.'s user avatar
  • 121
2 votes
0 answers
3k views

How do I determine the cause of a SCSI device reset?

I found this in /var/log/messages: Jul 27 03:59:46 localhost kernel: sd 3:0:1:0: [sdd] SCSI device reset on scsi3:1 I don't see any other error logs to indicate why the reset occurred. How do I ...
jersey bean's user avatar
2 votes
0 answers
459 views

How to create a device file and simulate behaviors of the Pseudo-devices?

I am trying to create a device that accept input and generate special output. To make it simple, say I want to create a device which accepts any input (like /dev/zero) and writes 00 ff 00 ff 00 ff .....
Eric Stdlib's user avatar
2 votes
0 answers
134 views

How to simulate adding new device (USB)?

I am trying to test the behavior of license after added new device (USB) in virtual machine. Are there any commands for simulating that?
user208240's user avatar

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