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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).

196 questions with no upvoted or accepted answers
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votes
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923 views

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 ...
7
votes
1answer
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 ...
5
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0answers
1k views

systemd-shutdown[1]: Failed to finalize DM devices, ignoring

Each time I reboot my laptop, that's running Kubuntu 20.04, I see this message right before it reluctantly reboots: systemd-shutdown[1]: Failed to finalize DM devices, ignoring Also, rebooting takes ...
5
votes
1answer
1k views

Why are there two entries per device on /dev/input/by-path

If I go to /dev/input/by-path I can see my input peripherals. I've got one keyboard and one mouse, and on my platform the output is: pci-0000:05:00.0-usb-0:1.2:1.0-event-kbd pci-0000:05:00.0-usb-0:1....
5
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0answers
1k 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 ...
5
votes
1answer
1k views

Remote Mouse netcat (/dev/input/mice)

I was playing around with nc and I'm discovering how powerful and versatile this tool is. I was wondering how the file /dev/input/mice works because when I do cat /dev/input/mice you see the output, ...
5
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0answers
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 ...
4
votes
0answers
69 views

Why root user is not getting “Device or resource busy” response?

I am working with GSM modem and using /dev/ttyUSB2 device. Device is having proper rights: $ ls -alh /dev/ttyUSB2 crw-rw---- 1 root dialout 188, 2 May 25 19:44 /dev/ttyUSB2 I am in dialout group ...
4
votes
1answer
625 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, ...
4
votes
1answer
565 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 ...
4
votes
1answer
653 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 ...
4
votes
0answers
4k views

Check if Keyboard and Mouse are plugged in

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: ...
3
votes
0answers
503 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 ...
3
votes
0answers
980 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 ...
3
votes
0answers
187 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 -...
3
votes
0answers
307 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 ...
3
votes
0answers
1k 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 ...
3
votes
0answers
69 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 ...
3
votes
0answers
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 ...
3
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0answers
113 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 ...
3
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0answers
152 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 ...
3
votes
0answers
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: ...
3
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0answers
673 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 ...
3
votes
0answers
205 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 ...
3
votes
0answers
390 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 ...
3
votes
0answers
940 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 ...
2
votes
1answer
130 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. ...
2
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0answers
97 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 ...
2
votes
0answers
699 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 ...
2
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0answers
1k 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
2
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0answers
2k 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: ...
2
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0answers
70 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)?
2
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0answers
215 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 ...
2
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0answers
983 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 ...
2
votes
0answers
135 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 ...
2
votes
0answers
585 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 ...
2
votes
0answers
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 ...
2
votes
1answer
545 views

Why does kpartx use a new loop device each time?

I'm running kpartx from within a python script as part of a custom OS build I'm trying to do. I'm using python sh module to run bash commands. sh.kpartx("-as", image) is how I attach my image. Then ...
2
votes
0answers
842 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 -...
2
votes
0answers
2k 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 ...
2
votes
0answers
239 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 .....
2
votes
0answers
896 views

Lenovo yoga 510 touchscreen not working

I just got a Lenovo Yoga 510. I've installed Fedora 25 (as dual boot with MSWindows). But the touchscreen isn't working in Wayland nor Xorg. xinput list only shows the trackpad, keyboard, powerbutton ...
2
votes
0answers
1k views

USB touch screen not working with debian 3.8.13 (BeagleBone Black)

I have a waveshare 7" HDMI touch screen display rev 2.1(touch over USB port and HDMI display) (link for the product) and I want to interface it with BeagleBone Black. The manufacturer says the 7" ...
2
votes
0answers
562 views

Ethernet to USB adapter is not initialized as ttyUSB or ttyACM device

When I plug a Ethernet-to-USB adapter to my Ubuntu 14.04 on the USB port. I can see the Ubuntu has an extra ethernet device. However, I want to see /dev/ttyACM* type of device. I'm wondering why the ...
2
votes
0answers
1k views

udev: Passing parameters via $attr{key} does not work. How to solve it?

I want to enumerate my USB-UART bridges with my own script. The script shall be called with some attributes and return a new devfs node name. I tested the script on console: ./rc3e.py -d get-devfs-...
2
votes
1answer
535 views

Capturing data from a Fluke 1620a via Bash /dev/tcp file descriptor

I am currently trying to develop a script that will connect to a Fluke DewK 1620a Themo-Hygrometer and pull the current temperature and humidity readings from the device. While these devices have a ...
2
votes
0answers
427 views

Debian - cannot find cdrom

Having a jessie/sid debian box on kernel 3.13 (had same issue on kernel 3.10) First thing I notices was that k3b didn't find any optical drives. Then: The optical drives (dvd-writers) are found in ...
2
votes
0answers
678 views

Why is my embedded Linux unable to detect the sd device?

I have this ARM9 SAM9G25 embedded System, running a Linux 2.6.39 Kernel and a Busybox. I put the Images (of the bootloaders, and the linux+initramfs) on a SD so that in the end the system is booting ...
2
votes
0answers
798 views

Debian Wheezy USB2 ehci_hcd

I have a friend who decided to switch to Linux from Windows. I was helping her to get up and running as quickly as possible but we ran into a problem which I can't seem to solve. She uses Debian ...
2
votes
1answer
315 views

GPS Device Attached to Linux Mint 15

I purchased a Silvercrest GPS device from Lidl recently, but the software that came with it is a tad "underpowered" to say the very least and has no Linux support. I'm attempting to get at the raw ...