Questions tagged [kernel]

The kernel is the central component of the operating system and manages hardware, process scheduling, file systems, virtual memory paging, inter-process and network communication, etc.

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Raspbian - Real Time Kernel does not boot

I am trying to make a Raspbian kernel to support real time. To do that I cloned the latest kernel from raspbian github repository and applied the Real Time patch for 3.10.25-rt23 (https://www.kernel....
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Default kernel preemption vs real time patch?

Is the default Raspbian shipped with the real time patch? I'm using the .config of the default Raspbian installation as a base for a custom kernel compilation. In the section: >Kernel Features ...
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Multiplexing 4-digit 7-segment display is flickering

I connected a 4-digit 7-segment display to the GPIO-port. It uses 8 ports for the LEDs and 4 ports for multiplexing via PNP-transistors. It is running so far with a loop written in C program: while(1)...
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2answers
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Getting kernel headers for raspberry pi 2

I'm attempting to create a virtual video device on raspberry pi 2 using v4l2loopback and prior installation of the v4l2loopback on their website in the Dependencies section they say that the kernel ...
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1answer
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Periodic task in kernel module

I currently developing a gpio based kernel module for a custom protocol. As per requirements of protocol, I have to send data, clock and enable signal to output device throgh gpio. This data is 16-bit....
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1answer
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No modules found in custom Arch kernel

In order to test the patch linked to in the following post: https://github.com/raspberrypi/linux/issues/29#issuecomment-6884170 I need to compile a custom kernel for my Pi. To do this, I followed the ...
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1answer
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Boot the Raspberry Pi 2 with custom kernel and initramfs

I want to boot my Raspberry Pi 2 with a custom configuration. Therefore I have a kernel image and an initramfs file. The /boot directory looks like this: /boot/my_kernel.img /boot/my_initrd.img I ...
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1answer
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How to change the kernel commandline for ArchLinuxARM on Raspberry Pi effectly?

I'm using the raspberry pi with the latest ArchLinuxARM image. I'm having issues with the linux kernel and it randomly panics with 'kernel paging request' errors. I've found a solution to enable ...
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1answer
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Respberry Pi fails to boot with custom kernel

I'm trying to cross compile my kernel with touchscreen enabled, however my Respberry Pi fails to boot with the custom kernel. I was trying to compile the kernel on my ubuntu 10.4 (x64) with different ...
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1answer
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how to mount LCD/TFT screen on raspberry pi

Possible Duplicate Raspberry pi has an on-board DSI connector, If I buy an LCD or TFT or touch screen which has the DSI connector, could I mount it on the RPI? Does it require any additional firmware ...
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How do I roll back a kernel upgrade?

I am using the Occidentalis distro and stupidly ran apt-get upgrade without thinking about the repercussions. After a reboot I now am on a stock kernel, which means I lost kernel support for OneWire, ...
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Custom camera driver

Is it possible to write a driver, say for a OV camera, based on the existing drivers at the RPI git repo? As is I understand, with a datasheet for a sensor it should be possible to write a similar ...
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3answers
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CentOS Development Tools “No package kernel-devel available.”

When attempting to install the Development Tools on CentOS 7 I get the error: Error: Package: systemtap-devel-2.8-10.el7.armv7hl (base) Requires: kernel-devel However I can not seem to ...
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How can I read and write data to a Character Device File in Linux with PHP? [closed]

I'm trying to read and write to modules on the I2C bus on a Raspberry Pi using PHP. I'm using fopen() and fskeek(). Below is the code I've been trying to use to read data coming in from the physical ...
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DHT11 module compilation error

I try to compile the source code of DHT11 module given in [https://www.endian.se/content/?p=127] . I have followed the step of KERNEL compilation in [[http://bchavez.bitarmory.com/archive/2013/01/16/...
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1answer
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Raspberry Pi cannot create temp file for here-document: No space left on device

I have a 16 MINI SD CARD been used in my Raspberry Pi . I currently have a few programs installed like vim and etc which should only take up around 300mb in total. Why does it say my /root directory ...
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Where do I find the linux headers for an image?

I started with Raspbian 3.18.5 (Wheezy?) and did an rpi update and ended up with 4.1.10 (Jessie?). When I did a sudo apt-get install linux-headers the following packages were available: linux-...
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How to get a specific kernel version for Raspberry Pi Linux?

I'm trying to find the source for version 3.12.20, but the current 3.12.y version on GitHub is 3.12.24. I understand I can just update my current version, but shouldn't downloading the source for my ...
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Can I get better performance on Raspbian if I blacklist a lot of kernel modules in raspi-blacklist.conf?

I have a Raspberry Pi that is being used only for displaying a single webpage. I have the memory split set at 64M for the GPU. The display does not require sound, web-video, usb-devices, user-input. ...
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3answers
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Updating kernel/firmware to specific version

I've updated my rPi to the latest kernel/firmware using rpi-update and my Bluetooth dongle stopped working. I found this to be a known bug in 3.10.* branch of the kernel. Through tinkering and ...
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1answer
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What Distro Are The Stock Images Built For?

When I take a look at the firmware github repo, I can download kernel images. But to what distro do they belong to or are compatible with?
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Raspberry Pi 1 Model B+ end of life?

TL;DR My Raspberry Pi (Model B+) can't run the newest Raspbian (Stretch), suspected is that the kernel doesn't work. Anything with a kernel version above 4.1.19 will fail to load. Does this mean that ...
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Which kernel source is required to compile for Raspberry Pi?

I am trying to compile and build a kernel image for Raspberry Pi. I build my customized cross compiler tool-chain for Raspberry Pi using Buildroot. Successfully I got all tools which I needed. I ...
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1answer
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What does mkknlimg exactly do, and what is a trailer?

I recomplie the Raspbian kernel for Cirrus Logic audio card, following this description. https://github.com/CirrusLogic/rpi-linux/wiki/Building-the-code and I wonder what does mkknlimg exaclty do. ...
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1answer
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Raspberry Pi-2 with mainline Linux kernel

With several nice commits landing into the mainline of Linux Kernel for version 4.5, is it already possible to compile and boot a mainline kernel (e.g. 4.5-rc6) on a Raspberry Pi 2? If yes, then what ...
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1answer
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Pi 3B+ jack audio inputs and low latency

Related: Raspberry Pi 3 audio input? I need to be able to input several jack microphones (minimum 2, more could prove useful) to my raspberry, to do some audio processing (between all inputs), and ...
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1answer
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How to get kernel source corresponding with the kernel installed by rpi-update

After an upgrade using rpi-update the kernel could be upgraded. The script download the kernel from an other gihub repository rpi-firmware. Till now, in order to get the kernel source, I download ...
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1answer
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How to tell if I am running the latest version of the Raspbian kernel?

I just finished building the Raspbian kernel according to the instructions in Raspberry Pi Kernel Compilation Guide. Prior to this I was running the latest build from raspberrypi.org, 3.6.11+ #358. I ...
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1answer
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Schedule periodical processes

I have a project that I´ll be using RaspBerry Pi to make a controller for process control. To do that I need to schedule processes periodically. Does anyone know how I could do that? So I have to ...
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1answer
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Unloading kernel module does not remove /dev/ device file

I have had success following tutorials for developing kernel modules, running them on a Ubuntu 12.04 LTS virtual machine. Particularly the example in this tutorial works fine on Ubuntu on a 3.2.0 ...
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1answer
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Execution interruption while holding a kernel spin lock

I want to toggle an GPIO pin with a certain accuracy. (i.e. latency about 1 us). I have a Raspberry Pi 3 model. Therefore I wrote a simple test kernel module. The toggling loop does basically this: ...
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1answer
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What repository to add for apt to find raspberrypi-kernel?

In the default Raspbian image I find *raspberrypi* kernel, bootloader, firmware etc. Using a bootstraped Installation I don't find them but using the same entries in /etc/apt/sources.list. In ...
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1answer
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How do I get/compile a source package for version with “+”?

I have a version with a "+" in it - what does this mean? How do I figure out which source I want if I am compiling a patch? How do I go about finding it? Any links are much appreciated! Example $ ...
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1answer
682 views

Use of gpio interrupt 2 rather than interrupt 3

I have studied in bcm2835 manual that its gpio peripheral can generate three interrupt lines. But in the same manual (interrupts section) I found that there are four gpio interrupts, gpio_int[0] to ...
3
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1answer
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infinite loop while building script for kernel

I have replace 3.18 kernel with 3.10 kernel for some kernel module checking on raspbian. Now when I tried to build that module I got error for kernel script (genkmsys, fixdep etc etc). So, I tried ...
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1answer
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PANIC: VFS: Unable to mount root fs on unknown-block(179,2)

I unplugged my RPi (RPi#1) and moved it to another power outlet, and plugged it back in. RPi#1 is the brains of my distributed setup, containing the database and biggest SD card. All of the data my ...
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1answer
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Is the Raspberry Pi 4 vulnerable to the Spectre exploits?

Now the new Raspberry 4 has moved to ARM A72 cores, it's vulnerable to the spectre issues according to ARM. Processor Variant 1 Variant 2 Variant 3 Variant 3a Variant 4 Cortex-A72 Yes Yes**...
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1answer
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Raspberry Pi ArchLinux ARM 64bit - WiFi card not detected

I installed the new 64 bit kernel tarball of archlinux for Raspberry Pi 3. I wanted to set it as access point but I didn't find any WiFi interface. Instead of 32 bits version, the WiFi chipset is ...
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4answers
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How can you get video display using the FLIR thermal camera

I am working the Lepton FLIR thermal camera and trying to get a video stream from it using the Raspberry Pi. When I hooked it up and used the already existing code I got a red box on a black screen. ...
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2answers
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What is the right value of GPIO_BASE in Linux kernel for Pi?

According to "BCM2835 ARM Peripherals" page 90, the GPIO registers start from 0x 7E20 0000. While according to kernel file: arch/arm/mach-bcm2708/include/mach/platform.h, as below. #define ...
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Problems compiling kernel on Raspberry Pi

I'm trying to compile the kernel from source on the Raspberry Pi, so I fetched it from git@github.com:raspberrypi/linux.git, and I'm using the stable branch (rpi-3.6.y). I did the following: git ...
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1answer
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GPIO in kernel module: alternative to gpio_set_value

Goodmorning, i've found out that in a kernel module gpio_set_value and gpio_get_value are very slow (60 useconds). According to this site, http://codeandlife.com/2012/07/03/benchmarking-raspberry-pi-...
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1answer
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Raspberry PI freezing

I am working on a project to getting data from serial device and transmit it to web. I am using kernel 3.2.27 with busybox few start up scripts like sysfs and proc, wvdial daemon to dial USB modem for ...
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1answer
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Unable to handle kernel null pointer dereference

Okay, so this is one of various problems I'm having trying to get by RPI/ModelB working. Here are the steps I've followed and the errors I've run into. Installed Arch on 4GB SD card following this ...
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How do I build just some in-tree modules for the Raspbian kernel?

I would like to cross-build some in-tree modules (capi, gigaset) that are included in the kernel source but not in the standard Raspbian kernel. My toolchain is using the tools from https://github....
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How can I install the latest kernel from kernel.org to Arch Linux ARM for Raspberry Pi 3 model B?

I am using Arch Linux on Raspberry Pi 3 model B. I want to install a newer kernel (currently I have 4.14.94-1-ARCH kernel installed) I have downloaded and compiled the mainline kernel 5.0-rc5, which ...
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1answer
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How do I add an i2c device to the device tree?

I am trying to add an mpu 9250 to the device tree of my RPi 3 A+ so that my custom driver's probe function will be called. I have followed this documentation about the Raspberry Pi device tree and ...
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Why doesn't extract-vmlinux work with Raspbian's /boot/kernel*.img?

To monitor if a reboot is necessary, I wanted to compare the version of /boot/kernel*img against the version of the running kernel. To get the kernel version of a compressed linux kernel image (...
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1answer
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No USB with upstream kernel

I have built a kernel for Raspberry Pi 2 using the latest upstream kernel (version 4.15-rc5): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ I configured it with ...
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Implementing a system call for CPU hotplug on RPI3/ModelB

My goal is to implement a system call in linux kernel that enables/disables a CPU core. First, I implemented a system call that disbales CPU3 in a 4-core system. The system call code is as follows: ...