embedded-linux

问题 Say on a non-RT Linux kernel (4.14, Angstrom distro, running on iMX6) I have a program that receives UDP packets (< 1400 bytes) that come in at a very steady data rate. Basically, the essence of the program is: while (true) { recv( sockFd, ... ); update_loop_interval_histogram(); // O(1) } To minimize the maximally occuring delay time (loop intervals), I started my process with: chrt --fifo 99 ./programName setting the scheduler to a "real-time" mode SCHED_FIFO with highest priority. the CPU

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 8 years ago . How to get signal from kernel space to user space? 回答1: To get the signal from kernel to user space use the following code in your user space and kernel space code as below : user space application : signal(SIGIO

问题 I stumbled upon very strange issue with GCC. The issue is 25% drop in performance. Here is the story. I have a pice of software which is fp32 compute intensive (neural networks compiled with TVM). I compile it for ARM (rk3399 device), here is info: gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/5/lto-wrapper Target: arm-linux-gnueabihf Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.12' --with-bugurl

问题 I stumbled upon very strange issue with GCC. The issue is 25% drop in performance. Here is the story. I have a pice of software which is fp32 compute intensive (neural networks compiled with TVM). I compile it for ARM (rk3399 device), here is info: gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/5/lto-wrapper Target: arm-linux-gnueabihf Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.12' --with-bugurl

问题 I stumbled upon very strange issue with GCC. The issue is 25% drop in performance. Here is the story. I have a pice of software which is fp32 compute intensive (neural networks compiled with TVM). I compile it for ARM (rk3399 device), here is info: gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/5/lto-wrapper Target: arm-linux-gnueabihf Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.12' --with-bugurl

问题 I m building my own Yocto distro based on i.MX6 using Yocto 4.14-sumo and QT5.12 recipe. The embedded Yocto build works well. But when I generate sdk , by launching : bitbake abl-image-qt5 -c populate_sdk I get the following error output on nativesdk-qtbase recipe : ERROR: nativesdk-qtbase-5.12.0+gitAUTOINC+13ed06640c-r0 do_package: QA Issue: nativesdk-qtbase: Files/directories were installed but not shipped in any package: /opt/abl-imx-fb/4.14-sumo/sysroots/x86_64-ablsdk-linux/usr/share /opt

问题 I m building my own Yocto distro based on i.MX6 using Yocto 4.14-sumo and QT5.12 recipe. The embedded Yocto build works well. But when I generate sdk , by launching : bitbake abl-image-qt5 -c populate_sdk I get the following error output on nativesdk-qtbase recipe : ERROR: nativesdk-qtbase-5.12.0+gitAUTOINC+13ed06640c-r0 do_package: QA Issue: nativesdk-qtbase: Files/directories were installed but not shipped in any package: /opt/abl-imx-fb/4.14-sumo/sysroots/x86_64-ablsdk-linux/usr/share /opt

问题 As we all know, in the CAN bus communication protocol, sender know whether the data was successfully sent. I send socketcan data as follows. ret = write (socket, frame, sizeof (struct can_frame)); However, even if the CAN communication cable is disconnected, the return value of ret is still 16(=sizeof (struct can_frame)).I queried the information and found that the problem was due to the tx_queue of the network stack used by socketcan. When write is called multiple times, the buffer is full

问题 I am building an embedded linux distro on a Beaglebone Black (AM335x chip Cortex-A8 Arm-v7 Instruction set) using crosstool-NG, U-Boot, Kernel (5.5.5) and buildroot. When compiling the kernel I am getting this error message: /tmp/ccxFZlyN.s: Assembler messages: /tmp/ccxFZlyN.s:39: Error: selected processor does not support `isb ' in ARM mode /tmp/ccxFZlyN.s:90: Error: selected processor does not support `isb ' in ARM mode /tmp/ccxFZlyN.s:371: Error: selected processor does not support `isb '

问题 I built a core-image-sato image with the following configuration: MACHINE = "intel-core2-32" The generated image size is nearly 1.2 GB. After i add "x11vnc" package, the size is reduced to 380 MB. This image doesn't boot successfully on the hardware. Why is the image size reduced instead of increasing How can we debug what is going wrong? 回答1: The core-image-sato image you use inherits core-image.bbclass, which sets a default value of IMAGE_INSTALL using the ?= operator. This means that if