Calum Lind cas--

Diagnosing spurious wakes

This gist documents my attempts to get to the bottom of spurious wakes after installing Ubuntu 20.04 LTS on my system.

Initially, I thought it might be another system on my network sending Wake-on-LAN (WoL) packets. Then I thought it might be a known XHCI spurious wake kernel issue. And lastly, I finally resolved things by actively disabling the ability of USB devices, e.g. the mouse, to wake the system.

Update: I later came up with a better way of disabling wake-on-mouse that's covered here.

Note: as one of these steps, I upgraded the system BIOS - while this didn't resolve this particular issue, it did resolve an annoying issue with the graphic state not being properly restored for certain applications after wake-up.

Comments

A delicate matter, requiring taste and judgement. I tend to err on the side of eliminating comments, for several reasons. First, if the code is clear, and uses good type names and variable names, it should explain itself. Second, comments aren't checked by the compiler, so there is no guarantee they're right, especially after the code is modified. A misleading comment can be very confusing. Third, the issue of typography: comments clutter code.

Rob Pike, "Notes on Programming in C"

Interactive Matplotlib (while in REPL)

Matplotlib can be used in an interactive manner either in the REPL or as part of a script. Let's assume you're using export MPLBACKEND='Qt4Agg'.

To do this you need to switch on interactive mode:

import matplotlib.pyplot as plt
plt.ion()

Adventures in Python Core Dumping

After watching Bryan Cantrill's presentation on [Running Aground: Debugging Docker in Production][aground] I got all excited (and strangely nostalgic) about the possibility of core-dumping server-side Python apps whenever they go awry. This would theoretically allow me to fully inspect the state of the program at the point it exploded, rather than relying solely on the information of a stack trace.

	import argparse
	import os
	import warnings

	import mercantile
	import rasterio
	from pmtiles.tile import Compression
	from pmtiles.tile import TileType
	from pmtiles.tile import zxy_to_tileid
	from pmtiles.writer import Writer

	#!/usr/bin/env python3
	#
	# Copyright (c) 2021 Jasper Lievisse Adriaanse <j@jasper.la>
	#
	# Permission to use, copy, modify, and distribute this software for any
	# purpose with or without fee is hereby granted, provided that the above
	# copyright notice and this permission notice appear in all copies.
	#
	# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

	Encrypting hard drives without reinstalling Ubuntu
	===================================================
	Gijs van Tulder, 26.02.2019, last update 04.03.2019

	This is a list of the steps I took to encrypt the partitions on my
	Ubuntu 16.04 laptop with the LUKS encryption system. Encrypting the
	partitions took some time but was relatively easy. Getting the system
	to boot afterwards was a little trickier, but doable.

	Obviously, these steps might not work for you. Follow them at your

	#####################
	#
	# Use this with or without the .gitattributes snippet with this Gist
	# create a fixle.sh file, paste this in and run it.
	# Why do you want this ? Because Git will see diffs between files shared between Linux and Windows due to differences in line ending handling ( Windows uses CRLF and Unix LF)
	# This Gist normalizes handling by forcing everything to use Unix style.
	#####################


	# Fix Line Endings - Force All Line Endings to LF and Not Windows Default CR or CRLF

	# -- mode: ruby --
	# vi: set ft=ruby :

	PASSWORD_PATH = ".password"
	PASSWORD_ID_PATH = ".password_id"

	# Make sure to have installed vagrant-triggers plugin
	# > vagrant plugin install vagrant-triggers

	# After the first `vagrant up` stop the VM and execute the following steps

	import requests
	from requests.adapters import HTTPAdapter
	from threading import Thread
	import logging

	logging.basicConfig(filename='out.txt', level=logging.DEBUG, filemode='w')
	requests_log = logging.getLogger("requests.packages.urllib3")
	requests_log.setLevel(logging.DEBUG)
	requests_log.propagate = True