João Aguizo joao-aguizo

Random "Freezing" with AMD Ryzen CPUs

It seems that numerous GNU/Linux users (including myself) have been having issues with the system randomly "freezing" during light usage. From journalctl output and anecdotal accounts, it is speculated that the AMD Ryzen CPUs do not support other C-states for power management very well (at least on GNU/Linux distributions), and the freezing may be resolved by limiting the C-state of the CPU.

Possible Solution

Limiting the C-state of the CPU can be done through the addition of the following kernel boot parameter.

processor.max_cstate=1

Install OpenCV 4.10 with CUDA 12.6 and CUDNN 8.9 in Ubuntu 24.04

First of all install update and upgrade your system:

    $ sudo apt update
    $ sudo apt upgrade

Then, install required libraries:

Download

SIP
PyQT4

pyenv virtualenv

Switch to the Python version you want to use:

Ranger Cheatsheet

General

Shortcut	Description
`ranger`	Start Ranger
`Q`	Quit Ranger
`R`	Reload current directory
`?`	Ranger Manpages / Shortcuts

Git Subtree Basics

If you hate git submodule, then you may want to give git subtree a try.

Background

When you want to use a subtree, you add the subtree to an existing repository where the subtree is a reference to another repository url and branch/tag. This add command adds all the code and files into the main repository locally; it's not just a reference to a remote repo.

When you stage and commit files for the main repo, it will add all of the remote files in the same operation. The subtree checkout will pull all the files in one pass, so there is no need to try and connect to another repo to get the portion of subtree files, because they were already included in the main repo.

Adding a subtree

Let's say you already have a git repository with at least one commit. You can add another repository into this respository like this:

	cmake_minimum_required(VERSION 3.6)

	project(CmakeVirtualenv)

	enable_testing()

	# Find Python and Virtualenv. We don't actually use the output of the
	# find_package, but it'll give nicer errors.
	find_package(PythonInterp 2.7 REQUIRED)
	find_program(VIRTUALENV virtualenv)

	# /etc/udev/rules.d/99-usb-serial.rules
	# udevadm info --attribute-walk -n /dev/ttyUSB0 \|grep serial (can be used to get serial number)
	# udevadm control --reload-rules (reload rules)
	# udevadm trigger (re-add all devices)
	# see https://wiki.archlinux.org/index.php/Bus_pirate
	# for some reason, ATTRS{bInterfaceNumber}=="00" is not working, hence the use of ENV{}

	# single USB/serial adapters
	SUBSYSTEM=="tty", ATTRS{serial}=="A900TUKZ", SYMLINK+="ttyUSB_bub_1"
	SUBSYSTEM=="tty", ATTRS{serial}=="A700fdWb", SYMLINK+="ttyUSB_bub_2"