When we try to access a serial port device(i.e /dev/ttyUSB0) as a normal user, a Permission denied error will occur. Let’s take a look at permissions for those serial port devices:
1 | ll /dev/ttyUSB0 |
As we can see, except root user, dialout group also has permissions to those serial port tty devices. Hence, to allow normal user access serial port devices, adding normal user to dialout group will suffice:
1 | sudo usermod -aG dialout $USER |
There are several ways to achieve IPC, shared memory is one of those. In this post, we will try to create shared memory via mmap module in python.
kazam is an easy to use screen record tool for Linux. User can install it via apt install kazam on Debian based distribution. After recording, kazam supports to save as mp4 files, which are 4:4:4 by default. To make it available for typical player on other platform, we can covert it to 4:2:0:
1 | ffmpeg -i ${original.mp4} -vf format=yuv420p ${new.mp4} |
In AndroidX, TabLayout has been extended and moved to package com.google.android.material.tabs.TabLayout. This post will describe how to use TabLayout + ViewPager to create swipe views with tabs in AndroidX.
AWS IoT Getting Started: MQTT sample
SWUpdate is a popular embedded system update framework. I’m trying to bring up a OTA update system on stm32mp1, and this OTA system will base on SWUpdate. This post records steps need to be done to install SWUpdate system into Yocto Linux, and create a single copy image to test it.
Yesterday we found that nfsroot will get crash after systemd-networkd starts:
1 | nfs: server 192.168.0.101 not responding, still trying |
Notes about some useful Yocto debugging commands
Last and this weekend I spend some time on mounting NFS rootfs on STM32MP1… There are some PHY driver issues and permission issues troubled me a lot…
Today I just managed to boot kernel via TFTP on STM32MP1 board but steps I go through are quite different with i.MX8. Thus, I think there is a necessity to have a short note about this 🖋