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

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5
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1answer
287 views

How do I load initrd into memory to be passed to kernel when using kexec?

As the MIPS port of kexec doesn't support the --initrd param, I'm looking for workarounds to imitate the feature. According to Linux/MIPS wiki, MIPS kernels support rd_start and rd_size kernel command ...
0
votes
1answer
386 views

how do I include the qcserial module in the kernel?

I need a kernel compiled, featuring the qcserial module to have support for the Huawei EM 680 model (Gobi 3000). I got kernel 3.11.6 and can find the appropriate source file in ...
6
votes
2answers
182 views

Location of the kernel binary (when not in /boot)?

I failed to find the kernel binary in the standard location in /boot. I've also searched the whole file system for vmlinux or bzimage find / -iname vmlin* find / -iname bzimage However, this is an ...
1
vote
0answers
34 views

App consumes diferent %CPU if started at start-up or from prompt [closed]

I run an application in embedded system, and it needs to start at boot. However, I have a problem with it: when I execute it at boot (from rc.local script), it consumes nearly all the CPU, making the ...
3
votes
1answer
163 views

Wget download file ( do not overwrite ) auto update script

I want to write auto update script for my embedded device, which can check and download newer version of my program and extract the files on the device. The download center is hosted on remote web ...
3
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0answers
124 views

What is the difference between the output of TOP command and Oprofile?

In the top command one of the processes is always showing a CPU usage of 4 to 5%. But in oprofile the CPU usage is 0.004%. I do not understand this. And I also noticed that even when a process is in ...
2
votes
1answer
157 views

Which system calls could create a new process?

When executing ps command in my Linux system i see some user processes twice (different PID...). I wonder if they are new processes or threads of the same process. I know some functions in standard C ...
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41 views

What could keep a process in 'Runnable' state indefinitely?

I am developing for embedded Linux and I have found a critical bug when stability test is performed. After 1-3 days running at some points the system becomes inoperative. Kernel network stack keep ...
3
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0answers
32 views

Queuing disciplines are per-interface, what happen with interfaces using same device?

I have read about queuing disciplines here http://lartc.org/. I understand that for instance band 0 of pfifo policy is prioritized over band 2 within same qdisc, but what happen when i have ppp0 and ...
1
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1answer
49 views

Having several qdisc for each device, which is the first to process?

I have read about queuing disciplines here http://lartc.org/. Having this traffic shaping policy: .... qdisc pfifo_fast 0: dev ppp0 root bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc ...
0
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0answers
110 views

optimizing Debian wheezy for an embedded board

I have Debian 7.1 on an embedded board that I just use WiFi interface, openVPN, and run a C code. The code uses UDP socket to transfer data, and do some calculations and output some signal on GPIO. ...
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137 views

prioritize traffic for some bridge interfaces using prio qdisc

Im configuring my router to give preference to some WAN interfaces. This interfaces are named ppp0 (PPP interface), vc2 (RFC1483 bridge interface) and vc3 (RFC1483 bridge interface). I had understood ...
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0answers
101 views

how to enable java support to buildroot

I'm using buildroot 2012.08 version for building embedded linux. I'm looking for best solution to add java support. Is it possible to do trough buildroot?
1
vote
1answer
524 views

What could cause a run time remounting of my /var partition to be read only?

I have a buildroot generated embedded linux system (x-86 geode processor) using an initramfs but with /var and /etc mounted onto a compact flash device using the default mount options specified in ...
3
votes
2answers
2k views

What does ifup do when “/etc/network/interfaces” has an invalid netmask address?

The interfaces file looks like below: auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 192.168.0.130 netmask 250.255.255.0 gateway 192.168.0.254 As you can see ...
1
vote
1answer
1k views

/dev/console dynamic redirection

Is it possible to dynamically redirect all data sent to /dev/console into something else (for example - to /dev/null, /dev/tty9 or even /dev/null)? Of course, it can be done statically via ...
0
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2answers
94 views

embedded linux and powering usb stick

I have a problem where I need to read a usb-stick or a usb keyboard: When I plug in the USB stick or keyboard I can't get power to the device. dmesg says nothing I tried: for device in $(ls ...
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0answers
68 views

Creating JFFS2 image

I am working on Embedded Linux, trying to create JFFS2 file system in the host and trying to load it on a NAND device in the target board - Olinuxino a13 wifi using Livesuite. I successfully created a ...
4
votes
1answer
453 views

ttyS1/uart1 initialised but not accessible through /dev/ttyS1

I'm not sure at which level I am having a problem. System is a LeopardBoard DM368 running TI's own SDK / LSP / BusyBox kernel, the core Linux kernel is 2.6.x so using serial_core.c driver model. By ...
2
votes
1answer
404 views

Know when a memory address is aligned or unaligned

Im getting kernel oops because ppp driver is trying to access to unaligned address (there is a pointer pointing to unaligned address). Im not sure about the meaning of unaligned address. It means not ...
7
votes
2answers
1k views

Is it possible for a daemon (i.e. background) process to look for key-presses from a USB keyboard?

I'm working on an embedded Linux project where I will be developing a program that will run automatically on bootup and interact with the user via a character display and some sort of button array. ...
2
votes
1answer
590 views

How to custom build debian's busybox?

I'm building an embedded system based on debian 7, and I'd like to make the most out of busybox that comes with debian. The problem is default busybox build in debian seems quite minimal, for example ...
2
votes
1answer
565 views

What is the easiest way to draw graphics on Linux framebuffer?

I have some embedded Linux ARM chip with LCD display on frame-buffer. I connect to chip with serial console. I can access frame-buffer directly with low-level commands. However I need to draw some ...
1
vote
1answer
455 views

mmcqd hangs and burns the CPU on the embedded device

On my embedded system I'm writing an intensive video stream to SD. I don't mount partitions, just write to /dev/mmcblk0p1. After a while my writing process hangs. I get [16952.240000] INFO: task ...
0
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1answer
33 views

Adding access to PPP

I have a PPP connection over USB (dev ppp0), and an eth0 connection. My Linux box has IP 192.168.1.1, I have a second Windows PC with an IP of 192.168.1.3. The ppp conection is 192.168.1.2 - which is ...
1
vote
1answer
717 views

How to configure linux to output to monitor

I'm currently running a lightweight Debian distro on a development board from Compulab. I have to login to the system via serial port everytime. The system has graphical card and the driver is ...
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0answers
137 views

Compiling a simple character device driver as a module

I wrote a simple character device driver & wanted to cross-compile it for craneboard (ARM architecture). My file name is gDev.c. I copied the file to kernel/drivers/char directory in craneboard ...
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0answers
117 views

Changing Android files in root directory

Does anyone know how (if it is possible) to change Android files stored in root directory, particularly logo.rle? I want to change my boot splashscreen, changing the file, which is stored in /. I have ...
2
votes
1answer
422 views

How enable watchdog?

I'm struggling with the watchdog timer (wdt) for a while. I can't get it working. My microcontroller is a AriaG25, based on the AT91SAM925. I have used this tutorial to compile the kernel. The ...
0
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2answers
357 views

How do I send text to a USB device?

I'm trying to get the "Torobot" USB servo controller to work with Angstrom on a Beagle Board XM. The servo controller registers as a USB device. The device just takes simple text commands, but there ...
1
vote
2answers
185 views

Which embedded Linux platform supports Suspend to RAM?

I am trying to save maximum energy for a certain embedded Linux application. Currently I am using Raspberry Pi. But it looks like Raspberry Pi doesn't support Suspend to RAM. What alternative embedded ...
1
vote
1answer
739 views

Beaglebone Black Device Tree for LCD4 cape

The device tree for LCD4 cape is located at /lib/firmware/BB-BONE-LCD4-01-00A1.dts When I looked into it, the declaration of those GPIO buttons confuse me. There are five buttons according to ...
1
vote
1answer
207 views

can linux be configured to blink an LED (GPIO) on disk activity?

I'm hoping to blink an LED that is wired up to a GPIO line whenever the USB connected disk has activity is there an easy way to pull this off?
3
votes
1answer
160 views

Is it possible to have two seperate one way (simplex) serial ports to make single tty device?

I am building embeded device, which has IR comunication with PC and it will have two IR Led/detector pairs which are one-way and are setup like this: IR source input commands -> near embeded device ...
1
vote
1answer
217 views

Using ncurses for basic GUI on a process started inside an init script

I have a custom written application that runs on a embedded setup (buildroot). My application has to run every time the target device boots up and so I wrote an init script to do this and it works ...
2
votes
1answer
428 views

What is the meaning of the errors from my cpio command?

I have been using the following command on my system to create the .cpio archive to create an initramfs for my embedded target device sudo find . | cpio -H newc -oc > ~/initramfs.cpio This has ...
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0answers
271 views

Linux embedded: change time zone

I'm working on an embedded system with linux. I'm trying to change the timezone used by the operating system and I'm doing this by copying the timezone file from /usr/share/zoneinfo to /etc/localtime ...
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0answers
105 views

Data loss prevention ( or recovery) in a MySql db in embedded systems

I have a little ( big ) problem with a MySql application that write on a SD card or a Compact Flash. After a data loss ( a power failure , for example) , if I try to retrieve the data of my db , it ...
1
vote
1answer
914 views

Copy/Mirror traffic to WAN interfaces without “iptables tee” support

I want to copy every outgoing packet to other WAN interfaces but my iptables (v1.2.7) doesn't have TEE target support. I wonder if there is another way (maybe using iproute2 or ebtables) to copy every ...
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0answers
88 views

No network interface for the lan9118 emulated on QEMU 1.4.0 overo machine

Im using QEMU 1.4.0 Ubuntu 13.04 distribution. Im trying to make the virtrual machine part of the host network so Im ussing this command: sudo qemu-system-arm -M overo -m 1024 -sd ./test.img -clock ...
2
votes
1answer
108 views

How can I find the Secure Attention Key (SAK) on my system and can I disable it?

In answer to My process was killed but I cannot understand the kernel notice, I was pointed to some documentation on the Secure Attention Key (SAK) on Linux. I have a embedded system generated using ...
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0answers
120 views

omap3530/3630 emulation on QEMU for overo and beagle machines

On QEMU's source code for beagle and overo I can see that the cpu emulated is the OMAP3430. I will like to know if it's a way to make QEMU emulate OMAP3530/3630 cpu's for those machines? On bealge : ...
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0answers
103 views

About Ingo Molnar's Realtime Preemption patch

Does Ingo Molnar's Realtime Preemption patch support ARM cortex-A8?
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0answers
117 views

Are there any good Embedded Linux image builder? [closed]

I'm looking for an image builder to create several Embedded Linux images for different ARM boards. I know the following image builder: linaro, buildroot, openEmbedded, yocto If I've missed one, ...
2
votes
2answers
570 views

ttyO ports do not have the good port address on QEMU 1.4.0 running image for beagleboard-xm

I'm running an Linux Image (kernel 3.2.8) for beagleboard-xm on QEMU's 1.4.0 emulator Ubuntu distribution for 13.04. My image is created using Buildroot beagle_defconfig. I added some pkgs to be able ...
2
votes
1answer
188 views

CONFIG_GPIO_SYSFS makes /sys/class/leds disappear

I have an embedded Linux board I'm working on, with a button and a couple LEDs. By default, I can control the LEDs via /sys/class/leds/redled/brightness However, I have no way to monitor the ...
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0answers
31 views

Spurious “command not found” [duplicate]

I am in the process of trying to build and install pjsua on my embedded board running linux with a kernel which is a variant of 2.6.18.. The board is booted via nfs from my filesystem. I have built ...
0
votes
1answer
89 views

Why does exec file generate 4 processes in Linux? [closed]

I build my RTAI-model-source(generated by simulink) in CygWin with gcc-linux-4.1 (cross-compiler of CygWin) on Windows, and generate ELF successfully. and the ELF runs correctly on Ubuntu. After the ...
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vote
2answers
1k views

Why is my wlan0 interface on Angstrom (Beagleboard) “Not Associated”?

I'm installing a Angstrom (custom build, not the default build) on a Beagleboard XM. I can scan for wireless networks using iwlist and see the neighborhood wireless devices. I have set my SSID and ...
1
vote
1answer
215 views

compressed and uncompressed kernel on an embedded device

I have been using several different embedded boards that store kernel, init files, filesystem, etc. on partitions of a (micro)SD card. I notice in the example usage or instructions that compressed ...