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

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40 views

Why is my swap not being activated automatically via fstab?

I've got a Linux embedded system that I'm experimenting with (the Elektor Embedded Linux Made Easy board, based on the GNUBLIN http://en.gnublin.org/index.php/GNUBLIN-Elektor). I'm using the 3.3 ...
2
votes
1answer
22 views

Late running of scripts during bootup, ending with a reboot without the login prompt

I'm making a special "installer" for an embedded system where I'd like the kernel to boot up, execute a set of things very late in the process where the peripherals have been set up and then reboot ...
2
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0answers
22 views

redirecting output of /dev/fb0 to /dev/fb2

I am using IMX6 Saberauto board on Linux OS. I have 2 displays primary is HDMI and secondary is LVDS. I want to run 2 applications. One QT on primary display, which I am able to do. Second ...
2
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0answers
43 views

Can't login using serial on ttyO0 - BeagleBone Black

I boot Beaglebone Black, connected to my desktop by serial. It was working great, until now. Beagle is booting, output shows up on the console, but at the end I can't log in. I can't type the login, ...
1
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0answers
25 views

How do I know from a BeagleBone Black if it is connected via USB (as a client/slave)?

BeagleBone Black has an USB port which allows the user to access it through ssh. In general, we could say that when you plug it to a PC, the PC is the USB host and the BBB is the USB client. On the ...
0
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1answer
47 views

What are the disadvantages of uClibc?

I try to speed up my boot sequence, and somebody recommends to use the uClibc instead of Glibc. I've built an image with it, it gets smaller and faster to boot — but at which cost? Does anyone know ...
1
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0answers
39 views

cross compile embedded arm

I have the android 4.2.2 code in directory /home/sghPhone2 which compiles normal with make menuconfig but I need to compile a 4.4 kernel and possibly patch it but when I download the source from ...
2
votes
2answers
46 views

tftpput in U-Boot: error: 'Access violation' (2)

I have enabled CONFIG_CMD_TFTPPUT in U-Boot, but I am not able to use it. I have set the serverip and ipaddr environment variables. When I use it as follows, it times out: u-boot# tftpput ...
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0answers
33 views

Is there a limit of GPIOs that can be used in Linux?

When it comes to use GPIOs, is there a limited number that can be used in Linux (except through the limitation of the physical availability/amount of the ports/pins) or is it theoretically possible to ...
1
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0answers
45 views

Unable to add serialport (nodejs module) when generating filesystem and cross-compiling tools for an ARM processor

I am using buildroot (version 2013.08.1) to generate the filesystem and cross compiling tools to implement embedded linux on a i.MX233 processor (ARM architecture). I add the serialport module by ...
1
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0answers
33 views

What are the two head.S files in linux source ?

In the linux source there are two different head.S files located at: arch/arm/kernel/head.S arch/arm/boot/compressed/head.S What is the puprpose of each one and what is the order of there execution ...
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0answers
7 views

WAN interface using his own queues for QoS different that the provided by Linux

My Linux embedded system have a WAN interface with the default pfifo_fast qdisc attached to it. The web interface for configuring the system let the user configure three Queues for the WAN interface ...
1
vote
1answer
62 views

Why isn't sda1 showing up in dev and how can I fix that?

I have an embedded Linux device and I was trying to copy some files to it. I plugged in a USB stick, the dmesg shows that it was recognized, but for some reason /dev/sda1 never showed up. I'm trying ...
3
votes
1answer
22 views

How do you ensure physical network interfaces always get the same interface name across reboots on an embedded Linux system?

For an embedded Linux system, if I have two or more network interfaces, how do I ensure that they always get the same interface names every boot In other words, I want, for example, eth0 to always ...
6
votes
3answers
70 views

What are the minimum root filesystem applications that are required to fully boot linux?

It's a question about user space applications, but hear me out! 3 'applications', so to speak, are required to boot a funcitonal distro of Linux: Bootloader - For embedded typically that's U-Boot, ...
0
votes
2answers
74 views

Kernel does not skip bad blocks when mounting filesystem

I am developing for an embedded Linux application using friendlyARM's micro2440. It runs on a Samsung s3c2440 ARM processor and uses squashfs in its NAND flash. Recently, some flash blocks went bad. ...
2
votes
1answer
82 views

How configurable is MPTCP?

I work on embedded Linux devices that usually have hard wired Ethernet as well as cell modem connections. If I were to use MPTCP would it be possible to easily configure the system to use eth0 all ...
1
vote
2answers
63 views

live dd over a mounted read-only root partiton

I'm trying to conceive a firmware update mechanism for a Linux-based embedded system without an additional initrd/initramfs/whatever. From within the running system which has a read-only mounted root ...
1
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0answers
34 views

Get log from kernel while loading

There is a arm/omap2-based device without ethernet, UART ports. It has usb connection with host, numeric keyaboard, LCD display. There is working U-Boot and kernel images for this. I'm trying to ...
0
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0answers
33 views

Interfacing with a custom camera in Linux on the beaglebone

I'm new to Linux development and need some pointers to help me get a camera (OV7670) working on a beaglebone running Debian. Using the camera capes as a guide, I've connected the camera to the GPMC ...
0
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0answers
28 views

Use Rsync with HTTP

Is it possible to use rsync with an HTML POST request? If so what would the rsync command look like? For example let's say using HTML5 I have this (bear with me going back to linux stuff): <form ...
16
votes
3answers
48 views

Can I achieve functionality similar to interrupts in Linux userspace?

One of functionalities I miss the most from "small embedded" in Embedded Linux is the interrupts. A signal appears on a specific pin, or other interrupt source is triggered and whatever was done ...
13
votes
4answers
96 views

Corruption-proof SD card filesystem for embedded Linux?

Recently we had a rather unpleasant situation with our customer - Raspberry Pi based "kiosk" used to display remote sensing data (nothing more fancy than a kiosk mode browser displaying a ...
3
votes
1answer
236 views

Which TCP congestion control algorithm is best for low speed radio modems?

On my project we have remote Linux nodes that communicate over the Internet via very low speed CDMA cell modems. The bandwidth on these modems is about 2kbyte/second and the RTT back to the server is ...
3
votes
1answer
86 views

Why doesn't 'ar' work like the manpage says?

I'm trying to use 'ar' included in Debian Wheezy armel version of binutils and it doesn't seem to operate like on other systems I've encountered. Some sample output from the command-line: $ ar ...
3
votes
1answer
78 views

Booting using initramfs instead of uramdisk

I am working on Zynq Microzed board. It is booting perfectly with uramdisk.image.gz but I trying to boot it with initramfs.cpio. In this regard I have made following changes in header files of ...
2
votes
1answer
93 views

Most reliable way to check for connected client?

I have an embedded Linux OS developed from scratch using Yocto. This talks to a Windows XP/7 client. The embedded OS runs a DHCP server and gives an address to the client. The problem is that the ...
0
votes
0answers
49 views

How can I make a configuration web page for a linux appliances? Any pre made solutions available?

I am putting together a bunch of embeded linux appliances that we will be installing at a few locations. Built the whole thing from scratch using Raspbian (debian based) and Raspberry Pis. There are ...
1
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0answers
39 views

Removed USB storage device is still mounted

I'm working on a embedded linux system based on busybox. Sometimes a USB device which is physically removed from the post is still displayed in mount, df or /proc/mounts. If I reattach the device, it ...
1
vote
1answer
47 views

How to get log from u-boot without com-port

U-boot is configured to print its logs into com-port by default. There is a device I can't receive this information (without uart/com). Can I configure u-boot to store its log strings into some place ...
1
vote
1answer
71 views

Conntrack TCP Timeout for state stablished not working

Im using a private IP address and I want to keep alive SNAT entries in my Router (Gateway) for at least two hours (some windows apps of my network are using TCP keepalive set to 2 hours). Gateway is a ...
0
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0answers
71 views

using sf probe to make u-boot faster

My uboot was running slow on a ARM cortex A9 processor based Xilinx zynq chip. Xilinx forum referred me to the following to solve this issue: +From 0a212cfc2dd4e4d1595de2ca2dde3f642e5707e7 Mon ...
0
votes
1answer
99 views

How can I boot with a compressed rootfs?

My problem is: I cannot use compressed rootfs (the kernel crashes during boot) but uncompressed ones work fine. What I did: I'm using Buildroot 2013.11 to generate Images for my embedded Linux ...
1
vote
2answers
68 views

Could not mount UBIFS on SD card

I guess this is not a big problem, still I can't see what's the matter. I'm building Images for an Embedded Linux (2.6.39) ARM9 System with Buildroot 2013.11, which is booting from an SD card. I was ...
4
votes
1answer
99 views

What does this dd command do exactly?

I have the an embedded device with this SD card: [root@(none) ~]# busybox fdisk -l Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes 4 heads, 16 sectors/track, 121008 cylinders Units = cylinders of 64 * ...
1
vote
1answer
54 views

WARNING: at kernel/irq/handle.c - after changing rootfs, but why?

today I changed from an image with initramfs to an image with separate kernel and rootfs. Theses images are used for an Embedded System (ARM9 SAM9G25), that is runnging with an Linux 2.6.39. During ...
0
votes
2answers
50 views

GPIO User Space App

GPIO User Space App describes user space application to test the GPIO. Another related link is Linux GPIO Driver. This would be running on a xilinx zynq board having an ARM Cortex A 9 processor. I ...
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0answers
126 views

How to cross compile linux kernel for ARM using GNU ARM toolchain? [closed]

I'm trying to cross compile latest Linux kernel 3.14 for ARM architecture. When I executed - make ARCH=arm CROSS_COMPILE=/usr/bin/arm-linux-gnueabi- The terminal gave me an error that: make: *** ...
1
vote
1answer
50 views

Uninstall Linux on an embedded board

I am using an embedded board, a FOX G20 V with an ATMEL AT91SAM9G20 processor. I would like to know first of all, which specific linux version I am using on this board, but also, how to remove it. ...
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0answers
77 views

Replacing default initramfs with my own

I followed this article to develop my own sample intramfs.cpio Now I have to put this in my kernel and compile. The procedure that I follw for petlinux is that I first run petalinux-config (and ...
0
votes
0answers
185 views

No filesystem could mount root, tried: jffs2

CPU: ARM Cortex A-9 This is the kernel command line that I appears in configuration menu root=mtd:jffs2 rw rootfstype=jffs2 console=ttyps0,115200 I have put three files in flash: BOOT.BIN in mtd0 ...
3
votes
1answer
295 views

While trying to open /dev/mtd2 for read/write access: Permission denied

Looks like my MTD2,and MTD3 partitions are write protected. The OS is booting from SD card on a ARM Cortex A 9 processor. root@Xilinx-ZC702-2013_3:~# mount /dev/mmcblk0p1 /mnt/ ...
0
votes
1answer
404 views

Debian and Systemd: breaking ordering cycle error

I'm a new embedded developer I'm trying to make systemd 37 work with freescale vybrid board (A5 and M4) running on linux-3.0 After boot with some breaking ordering cycle error, I check with ps ...
1
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0answers
47 views

tty not resizing properly

I'm running an embedded poky linux (linux-yocto v3.13) on a beagleboard. However, I'm having trouble when logging in over a serial using PuTTY: the terminal does not resize at all. Usually, the ...
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0answers
64 views

Interfacing ds1337 RTC on LPC17xx

I am a newbie and I am trying to understand how to interface DS1337(RTC) on LPC17xx Board. This board uses uclinux 2.6.33. .CONFIG: CONFIG_RTC_LIB=y CONFIG_RTC_CLASS=y CONFIG_RTC_HCTOSYS=y ...
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0answers
107 views

Arch Linux iMX6 capacitive touch LCD panel

I want to create an embedded system with a 7 inch capacitive touch screen and am planning on using Arch Linux on a Varscite made Freescale iMX6 quad based SOM development kit for this purpose. What I ...
2
votes
1answer
47 views

What are the two values in < > in a device tree .dts file ?

Following is the code snippet in a device tree file: flash@0 { compatible = "n25q128"; reg = <0x0>; spi-max-frequency = <50000000>; ...
3
votes
2answers
200 views

File system that never breaks (data loss acceptable)

There're several existing topics revolving around this issue, but what I seek is slightly different. I have an sd card on an embedded Linux and it suffers from power loss. I might be able to modify ...
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0answers
74 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 ...
3
votes
1answer
47 views

How to determine how many bytes / hr are being written to my SD card

I have a Debian embedded Linux system that uses an SD card as the RFS. What is a reliable way to determine how many bytes / hr are being written to the SD card?