Tvheadend starting slowly with a HD-901T2 DVB-T2 USB stick: The udev solution

The problem Having A HD-901T2 DVB-T2 stick on a Linux Mint 18.1 running a 4.4.0-53-generic kernel, Tvheadend started painfully slow. It took more than a minute before the web interface was available. And here’s why: Mar 11 10:22:35 tv systemd[1]: Starting tvheadend.service… Mar 11 10:22:35 tv tvheadend[6019]: * Starting Tvheadend tvheadend Mar 11 10:22:35 tv [...]

Linux / DVB / Command line: Watching multiple channels with single DVB adapter

Some (or all?) DVB adapters can be set to submit the entire MPEG-TS stream to the host, without filtering specific channels (actually, PIDs). This allows viewing more channel at a time. This is demonstrated below with ffplay, even though ffplay tends to get stuck when it goes to a live stream. It’s also not possible [...]

Linux / DVB: Playing with a HD-901T2 DVB-T2 USB stick

This is the successful version of a previous post, using a DVB USB stick that works, for a change. IMPORTANT: If you’re using a computer with USB 3.0, consider connecting the DVB stick to the computer through an external USB 2.0 hub. In particular if things break after an hour or so of playback (see [...]

Linux kernel: /proc/iomem-like output to kernel log during boot

In order to have something similar to /proc/iomem printed out to the console (and dmesg), this piece of code can be implanted somewhere in the kernel code (in my case it was arch/arm/mach-zynq/common.c). It may be required to add #include headers, depending on the file it’s added to. The original code that produces /proc/iomem is [...]

Linux: How to read through all files (checking a backup)

After finishing a backup to a USB stick, I like to verify that all is in place by reading through all files. Using the “tar” utility with verbose file output seemed to be a good idea. But… Don’t $ tar -cv . > /dev/null For whatever reason, the files aren’t really read. Only the names [...]

Linux Device Tree: What those status = “okay” are about

There are a lot of “okay” assignments in the kernel’s device tree. For example, arch/arm/boot/dts/zynq-zed.dts starts with /dts-v1/; #include “zynq-7000.dtsi” and later on there’s, among others, &sdhci0 { status = “okay”; }; &uart1 { status = “okay”; }; &usb0 { status = “okay”; dr_mode = “host”; usb-phy = <&usb_phy0>; }; Let’s look on the last [...]

bash: Jots on exiting the script

Trapping Call a function (byebye in this case) just before exiting a script: trap byebye exit Or a command: trap ‘echo “Farewell cruel world!”‘ exit It’s possible to catch various signals with “trap” as well. Quit on error In short: Have a set -e at the beginning of the script. It’s a global on-off feature, [...]

overlayroot (and permission issues) on Linux Mint 18.1

Introduction Wanting my media center computer to maintain consistent behavior and be tolerant to sudden power outages, I looked for a way to have the root filesystem read-only. This can cause problems with programs that expect to write to all kind of files allover, and media related software has this tendency to break when things [...]

Wallpaper / desktop background + other stuff on Linux Mint 18.1 / Cinnamon

Desktop wallpaper setting Get the current one: $ gsettings get org.cinnamon.desktop.background picture-uri ‘file:///usr/share/backgrounds/linuxmint/default_background.jpg’ And set it to another: $ gsettings set org.cinnamon.desktop.background picture-uri ‘file:///usr/share/backgrounds/linuxmint/edesigner_linuxmint.png’ Notes: The “file://” prefix is mandatory. There also an org.gnome.desktop.background attribute. Apparently, org.cinnamon.desktop.background overrides the former. For an effect on the screen, the “set” command must be run on the active [...]

Linux / DVB: Playing with command-line utilities

General Yet another collection of jots as I try out stuff. In this post, I’m playing with a Sin Hon DVB dongle, trying but failing to receive terrestrial TV with it. The OS is Linux Mint 18.1. I had also Kodi and Tvheadend installed on the system, but they aren’t discussed here. There’s no coherent [...]