Category Archives: Ubuntu

Fixing Ubuntu 16.04 massive internal microphone distortion

A while ago I upgrade from Ubuntu 14.10 to 16.04. Afterwards, my laptop’s internal microphone started to become massively distorted to the point that people on the other end of skype or hangouts calls couldn’t understand me at all.

Looking in the ALSA settings I noticed that the “Internal Mic Boost” was constantly being set to 100% and when I dropped this down to 0% everything went well. It seems on my laptop at least to be coupled with the “Mic Boost” which boosts both but without quite so much distortion, ie the “Internal Mic Boost” is a boost on top of the “Mic Boost” which is obviously a problem.

I couldn’t find much detail about how to configure this properly, so after some hacking around I was able to come up with the following solution. Go through every file in /usr/share/pulseaudio/alsa-mixer/paths, look for the section “[Element Internal Mic Boost]” if it is there. You should see a setting under that section like “volume = merge“. Turn that into “volume = off“. To prevent it being changed later when ALSA is updated, you can run:

I’d love to hear if there is a simpler way to work around this issue, but it works for me at least!

Making a BTRFS read-only snapshot writable

For the past few years I’ve been using btrfs on most filesystems that I create, whilst it’s pretty slow on rotating disk media now that most of my hardware is SSD-based there’s not much of a performance penalty (as long as you’re not using quotas to track filesystem usage). The massive advantage is the ability to have proper snapshot history (unlike any LVM snapshotting hacks that you may suggest) going back a long time with very little overhead. With a tool like snapper (which admittedly is tricky to get set up) you can automatically rotate your snapshots and easily recover any files that you accidentally changed or deleted. Alongside always using git for code repositories, this has saved my skin repeatedly!

Anyway, by default snapper creates read-only snapshots. But when trying to diagnose some database server file corruption I recently experienced I wanted to change a btrfs snapshot from read-only to read-write so I could update some files. After spending a while looking around in the manual and on stack overflow I couldn’t see any way to do this with the kernel/toolchain versions that I was using.

Then, the solution struck me. Simply create a read-write snapshot of the read-only snapshot and work off that. Sometimes it’s very easy to look at the more complicated way of doing things and forget about some of the easier solutions that there might be!

KUbuntu double login screen

More a note to myself, but hopefully it will be helpful to others too! After updating to KUbuntu 16.04 a few months back, I had an issue where when I closed the lid to suspend the laptop, and then opened it again it presented both a gnome login/password screen and then a KDE5 password screen. When I used the button, or some other times when I suspended it only showed the KDE 5 Plasma unsuspend prompt. After some googling around I found a SO thread which pointed me in the right direction.

Going in to the org.gnome.desktop.screensaver of dconf-editor I deselected the idle-activation-enabled, lock-enabled and ubuntu-lock-on-suspend options and I’ve not had this issue ever since