Archive for the 'Life' Category

Audio “popping” when using Wireplumber on Linux

As applications started and stopped playing sound my speakers were making an annoying “pop” after I updated my Lenovo P50 laptop to Fedora 35. This would happen scrolling through a twitter feed with embedded videos (even though the sound is disabled by default until you click, the browser must open the audio ready causing a pop).

Based on combining the advice in the following web pages:

I made a copy of the config file (as per the second link):

mkdir -p ~/.config/wireplumber/main.lua.d

cp /usr/share/wireplumber/main.lua.d/50-alsa-config.lua ~/.config/wireplumber/main.lua.d/

Then I edited ~/.config/wireplumber/main.lua.d/50-alsa-config.lua to add :

["session.suspend-timeout-seconds"] = 0,

Into the final apply_properties stanza in the file. It seems to work but I don’t know much about alsa so there may be a better workaround – if you know of one, let me know.

CentOS 7 on an HP MicroServer N36L with an AMD Mobility Radeon HD 5430

I have an aging N36L box I use at home as a file server on our internal network.

Today a yum update in CentOS7 (it has not been updated for a long time so there were a lot of packages) caused the graphics to be corrupt/crash (machine was fine in text only mode).

I tried a few different things:

  • the latest mainline kernel from
  • Fedora 29 (which rebooted immediately after logging into GNOME and had lots of graphical corruption in XFCE
  • Eventually downloaded CentOS7.3 from the archive and reinstalled using that. It’s a terrible work-around (and I didn’t keep logs or error messages). I used software RAID 1 with LVM on top.

Really this post is just to remind me what my dirty hack was if I need to do it again. I ought to collect logs and diagnostics of the problem and report it upstream.

TEDx Southampton 2016

TEDx Southampton 2016 happened today – the subjects were diverse and the speakers varied in style. I enjoyed most of them but there were two, in particular, that I thought might change my behaviour in future…

Tony Curran was speaking about the carbon-footprint of our food. He linked to the XKCD representation of the relative weights of the the population of land mammals. If you’ve not seen it before, the small fraction of wild animals might surprise you. Look at the fraction that is cows! Reducing the amount of beef we eat (even if you swap it for chicken) could have a big impact on the planet. He also talked about the importance of eating things in season and of choosing foods that come by land/sea not flown by air or grown in a hot house. He has a handy PDF guide to whch foods are in season.

Megan Streb talked about the importance of livable spaces. She extolled the virtues of knowing your neighbours, kids playing outside and communal outdoor spaces with seating. She talked about the possibility of closing streets for parties (or more regularly for kids to play). It was definitely food for thought and it gave me some ideas to think about which is what you hope for when you go to a TED event.

I’ll definitely be keen to go to a 2017 event if one happens.

Today I learned

Day 2 of Winchester Science Festival 2016. It’s an awesome event. If it happens next year: go!

A few random facts that I learned today:

  • The average time between a rabbit being bought in a pet shop and it being taken to a rescue centre is 6 weeks but they live 8-10 years. 
  • Rabbits make two types of poo – one (soft) designed to be eaten – they digest their food twice.
  • I saw an amazing video of a  rabbit attacking a snake.
  • Quite how quickly atmospheric CO2 is rising ‘The pump handle graph
  • In 1800 the UK had a life expectancy of about 40. It was even lower in almost all other countries.
  • At this point we’ll need to do carbon capture (BECS) to keep climate change to 1.5C
  • Deadly Nightshade is called Belladonna (‘beautiful woman’) because the berry juice was applied with a feather to dilate ladies’ pupil and make them look more attracted to a partner. The active ingredient atropine causes hallucinations and larger doses ~1 berry causes death.
  • Botulinum toxin (botox) is one of the most toxic things known to mankind. A pint could kill all living humans. Lethal dose is 1 nano-gram.
  • The placenta has viral DNA, what makes us mammals are genes captured from viruses: Mammals were made by viruses
  • ‘Unqualified’ volunteers have analysed images on the GalaxyZoo website and discovered type Ia supernova which are a ‘standard candle’..which help is measure the distance to other galaxies. You can volunteer time to help a number of science projects at the Zooniverse.

The Zooniverse talk was really inspiring, I’ll definitely be having a play!

Problems with Qt Creator installed in /opt

I’ve been doing a bit of fiddling with using Qt for developing mobile apps. When I installed the Qt SDK I installed it to /opt. This means the user running the IDE does not have write access to the IDE which has caused a number of problems.

  • Updating the SDK: If you run the SDK as the normal user, the “Help > Start Updater” menu option still exists and appears to work. It seemed to detect that I had sudo access and asked for my password but then hung using 100% CPU. Instead of using that menu option, I ran /opt/QtSDK/SDKMaintenanceTool as root which works.
  • Running the QEMU phone emulator: This failed with “Qemu finished with error: Exit code was 1”. To fix this, I ran QEMU manually:
    /opt/QtSDK/Madde/bin/mad remote -r dfl61-harmattan_2.2011.39-5 poweron -fg
    This showed I needed write access to the qemu disk images. As I’m the only user on the system*, I gave all users access:
    chmod a+w /opt/QtSDK/Madde/runtimes/dfl61-harmattan_2.2011.39-5/arm-qemu-rm680-*

Hope this helps someone stumbling across this via Google

* = Yeah. There was no need to install Qt into /opt – it just seemed tidier than putting it in my home directory