Questions tagged [embedded]

The use of Unix in embedded computer systems such as networking equipment, mobile phones, media players, set-top boxes, etc.

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"Connection refused" when I try to send a UDP packet with netcat on an embedded-linux board

I'm trying to send a binary packet to a local process, via netcat (nc), like this: nc -w 1 -u localhost 10000 < my_binary_packet.bin The output is: read(net): Connection refused Anyone know what'...
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Method to diagnose what my network Rx bytes are?

I'm working on an embedded Linux product (Debian 10.8 running on Atmel based SBC). When in its "normal rest state", it should be doing very little network traffic, NTP and one minute MQTT ...
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How to measure how long linux takes to shutdown

I need to calculate how long linux takes to shutdown. I am running an embedded busybox linux on ARM i.MX7. I looked in /var/volatile/log/messages but that only shows the last startup. I need to ...
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Use `last` command to show non-interactive sessions

We use the command last to show if other users connected to an embedded system. For interactive ssh-sessions this works fine. But we use MATLAB GPU coder which provides build code to embedded system. ...
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Wi-Fi Access Point has very low speed in one direction

We are creating an Access Point on an embedded device by using hostapd and dnsmasq. No iptables rule is set. We set it on 5Ghz (a/n) however max transfer speed is 6.1 Mbyte/sec. (Tried with scp and ...
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two modules for WM8962

As can be seen on https://www.kernelconfig.io/search?q=wm8962&kernelversion=4.19.165&arch=arm64 there are seemingly two different kernel modules for the audio codec WM8962 and they have ...
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How to access gpio-keys from a shell script

In my embedded linux system, I defined some GPIOs as keys in the device tree so I can use them as keys in my application. This works fine so far. Now I want to add an early startup script to respond ...
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How to wait for pulseadio before running chromium?

I'm developing an embedded board (Tinkerboard) based on Linux Linaro (Debian) OS 9.3. The board is basically a (webpage) kiosk where the browser is run by a sh script included the automatic scripts on ...
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How Yocto embeds systemd in end project?

How can I customize systemd source code? When I do bitbake, systemd appears in my end project, but I cannot find any source files of it in my local directories. I want to track down unit files ...
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How to install gcc-5 on Debian 8.10?

I am trying to install gcc-5 on debian 8.10 on a beaglebone green. I have looked at many threads, of which the following was the most promising. How to install GCC 5 on debian jessie 8.1 When I try to ...
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System is booting to "emergency/rescue mode"

This may not be the issue with Yocto itself but rather related to properly booting up Linux on Avenger96(STM32MP1) board. I am currently working on Avenger96 with Yocto(Dunfell). Aim is to implement ...
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U-Boot: is it possible to implement bootcount using a SPI EEPROM?

I'm referring to the u-boot bootcount/Kconfig for options to implement a boot counter. Options include DM_BOOTCOUNT_SPI_FLASH and DM_BOOTCOUNT_I2C_EEPROM. As it happens we will have a SPI EEPROM ...
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How to stream the linux framebuffer as video over http

I have an embedded linux system (yocto based) with a framebuffer UI (no X11) and a running web server. Now I'm asking how to "mirror" the screen contents to a web page. Think of it like a ...
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systemd debug (embedded case)

How to trace systemd unit files, to be specific, device unit files? I use 3.18 version of linux kernel. On my board after systemd has started, (mypartition).device runs and, I suppose, remounts the ...
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Cross-compilation: discrepancy between host and target gcc version

I'm developing C and C++ code for an embedded target running Linux equipped with an ARM aarch64 CPU (Cortex-A53). My goal is to develop on Windows (x86) with Visual Studio, that's why I'm trying the ...
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How to prevent NetworkManager from writing timestamps to /var/lib/NetworkManager/timestamps every 300 seconds?

I am building a headless embedded system based on Ubuntu where I need to minimize disk write activities to maximize eMMC life span. I have gotten all things which write to the disk managed with some ...
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How to write "Magic Number" boot block to the first sector of my flash drive

I want to try and see how the BIOS detects boot device using the magic number (0xaa55) by writing e9 fd ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 00 ...
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is it possible to install guix package manager to a buildroot environment?

Hello fellow linux users, I am creating a distribution with buildroot and I wanted to install a package manager (guix). The idea is to try to compile it with either make or GCC. Is this possible to do ...
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timedatectl: problem with NTP returning localtime instead of UTC time

On my embedded Linux, I have a problem with time zones: I'm trying to keep the UTC time in the RTC of the device. But somehow, timedatectl keeps adjusting time to the local time and not the UTC time, ...
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Why am I not able to load files from a partition with U-Boot?

For some reason, my U-Boot does not seem to be able to load files from my FAT32 partition: => mmc part Partition Map for MMC device 1 -- Partition Type: DOS Part Start Sector Num Sectors ...
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Is there a way to do delta updates for container images w/o a registry?

In the context of a non-connected machine which has limited space available, is there a way to update the container image using a diff/patch mechanism? Like you call docker pull but on a binary patch ...
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Integrate a younger qt version in an older yocto release

Our project is based on the meanwhile outdated yocto warrior, which was first modified by the vendor of our SoM. Then we integrated the FreeScale/NXP kernel into it because the mainline kernel did not ...
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How to make a static SPI driver module dependent

I have a custom SPI ethernet driver which I want to load only after the SPI main driver has loaded. If I add both drivers as static my ethernet driver is failing because the driver is loaded and is ...
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rsyslog: discriminate between boots with new files or break line

I've got a system that uses rsyslog for logging. Some of the messages being logged I want to store on the device (error messages) so that if something has gone wrong I can review them later. All works ...
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Shell/tty Access via USB or Bluetooth?

Overview I am in the process of reverse engineering the software on my Infiniti Q50 head unit, and I am trying to figure out the best way to get shell access. I have pulled the image off of the ...
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How to detect which disk my kernel booted from?

How could I detect from an early initramfs Linux shell script which bootable disk my kernel has booted from, especially when an identical(-ish) system could be installed on multiple disks? The use-...
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set sshd SELinux security context

I'm working on my custom board and on my custom UNIX-like O.S. . When I connect using ssh and no root users a receve this SELinux error: A valid context for could not be obtained. where user is not ...
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Trouble finding on-board serial port via UART: "-bash: echo: write error: Input/output error"

I have an old tv box that I wiped recently with Linux. I would like to connect a device to its onboard UART pins, to which I've soldered wires that connect to a UART adapter on my PC. I opened up a ...
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Cross-compile libgpiod library and use it in my program

I am trying to cross-compile a program with the "gpiod" library. My host pc has Ubuntu 18.04 and the target platform I am cross-compiling for is a Board with IMX8X SOM. I found source code ...
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LZMA compressed squashfs image bit-error fix algorithm

Long story short: NAND dump from embedded device. The device uses ubifs as a filesystem. Now, after fixing the dump, I'm left with the partitions inside it. Almost every partition inside has "A&...
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How to disable hot-pluggable CPU on ARM?

I have an ARM64 Cortex-A72 board running Linux 5.4.47. I want to check if the CPU hot-plugging is working correctly (it's needed for one project I want to use). Kernel has CONFIG_HOTPLUG_CPU enabled, ...
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Kernel panic - not syncing: Requested init /init failed (error -2)

Attaching a bit more of the boot log. HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages HugeTLB registered 32.0 MiB page size, pre-allocated 0 pages HugeTLB registered 2.00 MiB page size, ...
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"systemd-tmpfiles-setup.service" slow on read-only filesystem

On a headless embedded computer (booting on a read-only filesystem), I see that systemd-tmpfiles-setup.service is rather slow, and prevents other services to start earlier (I checked with systemctl ...
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syslog-ng does not include severity in its lines

I'm trying to configure syslog-ng in an embedded distro. I added the syslog-ng package. I was expecting the /var/log/ files to include their log severity / log level, but it isn't to. Any way to ...
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Keyring is ignored by apt

I'm trying implement apt-get on an embedded device. For testing I use one of the Raspbian repositories but apt-get update keeps telling me my keyring has an unsupported file format. I removed the old ...
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Banana PI M2M (allwinner A33/R16) WiFI drivers in mainline kernel

I'm trying to get the WiFi working on a Banana PI M2M using the mainline kernel. The device tree definition of the banana pi m2m is very incomplete sun8i-r16-bananapi-m2m.dts I successfully managed to ...
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Design process for custom hardware

We have a design for a custom board with multiple codecs that will be used with a iMX8 module. We haven't made a prototype yet. Hardware designer wants to test his assumptions to verify the SAI ports ...
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How to check if the memory is actually used by the OS in an Embedded Linux system?

This question needs additional clarifications. Background: I am working on an embedded system (Xilinx zynq ultrascale+) which consists of an ARM processor + FPGA. The memory map (if I were to use the ...
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Mapping gpio nodes in device tree to gpiochip in Linux

Suppose I have the following snippet in my device tree: gpio2: gpio@3xxxxxxx { compatible = "my-gpio"; reg = <0xaddr 0xoffset>; gpio-controller; #gpio-cells = <2>;...
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Do I need to unbind driver on embedded device?

I've been having an issue reading from gpio devices on an embedded device(usrp n310). I2cdetect gives "UU" for the particular devices that I'm trying to reach indicating that the devices are ...
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Linux distribution without GUI for start an app on boot

I'm new to embedded systems/softwares and wanted to develop a video player for my PI that runs when it starts. Something like Kodi or LibreELEC. The question I am now asking myself is that is there a ...
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How to keep a timing dependent C process from context switching

We have a process that is responsible for polling hardware at time-dependent intervals. We would like to dedicate a CPU core to this process. E.g. we want this process to remain runnable at all times. ...
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Updating Debian using Rauc

If I have a Debian OS running on a Spectra PC, can I update that debian OS using just rauc? I know one way can be to use Yocto to build my own custom linux. But I do not want a custom linux, I want to ...
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Sniffing traffic at embedded linux

Are there any sniffers out there? I'm looking for something that can be compiled for an embedded device. Important: I'm not limited in space. Therefore it can be any-size sniffer that can be compiled ...
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linux kernel cannot find init

I'm running Linux kernel 5.14 with u-boot on a custom ARM board with 32MB of ram and 1GB micro-sdcard. this proves that I have the init files in my rootfs: (u-boot command-line) U-Boot > ext4ls mmc ...
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Why ifconfig shows a different IP address

I have Embedded Linux devices connected to a local network via Ethernet cable connection. I access each device via their local IP addresses on subnet 192.168.34.0/24. For example, one device has 192....
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yocto: psplash custom executables do not get installed

Depending on the detected hardware I need to start one of two executables of psplash with different images, so in my psplash_%.bbappend I have SPLASH_IMAGES = "file://bootscreen1.png;outsuffix=...
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MLC NAND flash support in ubifs in 2021

I would like to ask about MLC NAND support in UBIFS as of 2021. I was recently bringing up a device with IMX6ULL and raw MLC NAND flash. I have built Linux 5.4 kernel, u-boot and rootfs (using ...
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Embedded device (NTC Chip) fails to reboot properly after watchdog triggers reboot

I've been trying to get an embedded Linux computer called the NTC Chip to reboot properly after the watchdog triggers a reboot. If the NTC Chip is disconnected from power and then reconnected it will ...
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how to build arm fdpic toolchain?

I've successfully compiled and ran Linux kernel on stm32H7 board (arm cortex-m7) now I want to write applications on it but unfortunately because it won't have a virtual memory (MMU), it can't run ...
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