embedded-linux

In the function declaration int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *), unsigned long irqflags, const char *devname, void *dev_id); Is dev_id an 'in' parameter or an 'out' parameter ? Where do we get this number from ? Dev_id is an input argument and must be globally unique. Normally the address of the device data structure is used as the Dev_id . It has value NULL if the interrupt line is NOT shared. It holds relevance only when the interrupt line is being shared. When it is shared, this parameter uniquely identifies the interrupt handler on the

I have a Linux kernel module that implements a character device driver. I've read through Linux Device Drivers and followed several tutorials. At this point, I have a simple module that provides open , release , and write file operations. I'm trying to use the Generic DMA Layer to create a streaming DMA mapping. I'm confused by the following excerpt from LDD: Many of the functions below require a struct device . This structure is the low-level representation of a device within the Linux device model. It is not something that drivers often have to work with directly, but you do need ot when

I'm currently working on an audio recording application, that fetches up to 8 audio streams from the network and saves the data to the disk (simplified ;) ). Right now, each stream gets handled by one thread -> the same thread also does the saving work on the disk. That means I got 8 different threads that perform writes on the same disk, each one into a different file. Do you think there would be an increase in the disk i/o performance if all the writing work would be done by one common thread (that would sequently write the data into the particular files)? OS is an embedded Linux, the "disk"

Closed . This question is opinion-based . It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post . Closed 6 years ago . I have a code which detects GPIO interrupt in a kernel module. Now,I am looking for a mechanism to notify user space upon detecting gpio interrupt from kernel module. Any example / code snippet with certain advantages/disadvantages over different options? I would appreciate your response. Take a look at the GPIO keyboard driver ( drivers/input/keyboard/gpio_keys.c ). It is a

I'm working on a Embedded Linux application and I would like to use GDB to debug it. The problem is that, although the Kit configuration seems fine (the Debugger option is correctly pointed to the GDB correspondent to the device's GCC - device is a Linux ARM), when I ask Qt Creator to run in debug mode it returns an error in the "Application Output": sh: gdbserver: not found This seems strange since, as I sad, the configuration is fine and no error about that is reported by Qt Creator in any moment before starting debug mode. I did some research on the web to find which was the exact steps to

I've seen a lot of examples how to run a QEMU ARM board emulator. In every case, besides SD card image param, QEMU was also always supplied with kernel param, i.e.: qemu-system-arm -M versatilepb \ -kernel vmlinuz-2.6.18-6-versatile \ #KERNEL PARAM HERE -initrd initrd.gz \ -hda hda.img -append "root=/dev/ram" I am palying with bootloaders and want to create my own bootable SD card, but don't have a real board yet and want to learn with an emulated one. However, if run as described above, QEMU skips bootloader stage and runs kernel. So what should I do to emulate a full boot sequence on QEMU so

Does someone know why I get the following after "sudo apt-get install libboost-all-dev": Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: libboost-all-dev : Depends: libboost-context-dev but it is not going to be installed Depends: libboost-coroutine-dev but it is not going to be installed Depends: libboost

I have a simple python application which does: acquire information from a GPS parse information store it in InfluxDB The package requirements: certifi==2018.4.16 chardet==3.0.4 idna==2.6 influxdb==5.0.0 pynmea2==1.12.0 pyserial==3.4 python-dateutil==2.7.3 pytz==2018.4 requests==2.18.4 six==1.11.0 urllib3==1.22 The above is generated by using: pip3 install pynmea2 pyserial influxdb In the OpenEmbedded Layers Index I have already found pyserial package for Python3 . Which implies on the board I just might need to do pip3 install pynmea2 influxdb . How do you go ahead writing my application's

I am building an image with Yocto/Poky release Daisy 1.6.3. What is the correct way or config file where to set the root password? The default password is empty and I can't find a place where to specify it. Here is what you have to do in your recipe. inherit extrausers EXTRA_USERS_PARAMS = "usermod -P p@ssw0rd root;" where p@ssw0rd is the password you want root user to have. This link may help you. As "debug-tweaks"'s goal is to set root's password empty, you must remove it from your EXTRA_IMAGE_FEATURES. Hector D Martínez As of Poky 2.1.2; to set the root password the following instructions