embedded-linux

问题 I am compiling Compiling QEMU for ARM. taking into refrence following link :-- http://opensourceforu.efytimes.com/2011/06/qemu-for-embedded-systems-development-part-1/ I am using following download :-- http://download.savannah.gnu.org/releases/qemu/qemu-0.14.0.tar.gz ./configure –-target-list=arm-softmmu $ make Link says :-- You will find two output binaries, qemu-arm and qemu-system-arm I did not get qemu-arm binary but qemu-system-arm is produced. How to get qemu-arm binary ? 回答1: Use the

问题 I am trying to run the "libwebsockets-test-server" that is installed with the LWS library, but it will not run because "lwsts[31616]: libuv support not compiled in". I have checked that libuv is installed (1.8.0). I also changed the setting for LIBUV in cmake and recompiled the library. LWS_USE_LIBUV = 1 How do I get the project compiled with libuv? I am on Ubuntu 16.04, cross-compiling using arm-linux-gcc. I have successfully compiled programs, loaded them to the embedded board (TS-7800),

问题 I have a custom board based on the imx28 CPU. The Serial port of the CPU is connected to the PCM output of a modem. I have to develop a driver for the modem's PCM interface to be a part of ALSA SoC. Can you point out some drivers in the kernel tree that reasembles with my setup? 回答1: See the Documentation/sound/alsa/soc directory in the Linux source. It explains how ASoC drivers are divided into three categories: Codec driver: These define the audio controls, interface capabilities, DAPM

问题 I am writing Linux user space application. where I want to invoke registered callback function in user space area from the kernel space. i.e. interrupt arriving on GPIO pin(switch press event) and registered function getting called in user space. is there any method is available to do this. Thanks 回答1: I found below code after lot of digging and perfectly works for me. Handling interrupts from GPIO In many cases, a GPIO input can be configured to generate an interrupt when it changes state,

问题 For testing purposes, I can drop cached memory by writing to the drop_caches file in Linux under the procfs. I can only do this as root. This is on embedded Linux so there is no sudo. sync; echo 3 > /proc/sys/vm/drop_caches I can write to the file programmatically in c++ by doing something from the post --> How to programmatically clear the filesystem memory cache in C++ on a Linux system? sync(); std::ofstream ofs("/proc/sys/vm/drop_caches"); ofs << "3" << std::endl; The challenge is wanting

问题 I am working on a shell script. I have a pre-built zImage. is it possible to know the kernel version from which this zImage was created? I have tried with the commands updated @ Getting uname information from a compressed kernel image, but both commands are failing. $ dd if=zImage bs=1 skip=$(LC_ALL=C grep -a -b -o $'\x1f\x8b\x08\x00\x00\x00\x00\x00' zImage | \ cut -d ':' -f 1) | zcat | grep -a 'Linux version' dd: unrecognized operand `3165585' Try `dd --help' for more information. gzip:

问题 I have a particular problem. Poll keeps returning when I know there is nothing to read. So the setup it as follows, I have 2 File Descriptors which form part of a fd set that poll watches. One is for a Pin high to low change (GPIO). The other is for a proxy input. The problem occurs with the Proxy Input. The order of processing is: start main functions; it will then poll; write data to proxy; poll will break; accept the data; send the data over SPI; receiving slave device, signals that is

问题 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

问题 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. 回答1: 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

问题 I'm trying to get /var/log to be persistent in my fido build. The default setting on poky is, that there is a symlink in /var which points log -> volatile/log . volatile is a mounted on a tmpfs. So far i figured out that the symlink should be created by the base-files recipe: volatiles = "log tmp" do_install () { ... for d in ${volatiles}; do ln -sf volatile/$d ${D}${localstatedir}/$d done ... I appended the base-files recipe so the link was not created, but it still turned up in my rootfs.