Old digital microscope was driving Ubuntu nuts!13 Nov 2022
Today I needed to check some connections in the PCB of my ST-Link V2 clone because I wanted to add the trace support following the nice explanations from here. However, my old brandless digital microscope (you know, they all look the same and come in a blue box…) refused to work. dmesg helped me find some repeated error messages (
Failed to query (GET_DEF) UVC control 4 on unit 1 or
Failed to query (GET_MIN) UVC control 4 on unit 1) and a little bit of google-fu did the rest. I found my system was suffering from a problem with
uvcdynctrl and the log file
/var/log/uvcdynctrl-udev.log was already at 68GB (?!?).
I learned this is a super old bug (first message is from 2011!) and it can slow down your system to a halt. Using
apt show and the very useful
apt-rdepends I noticed
uvcdynctrl just depended on each other… so following the suggestion and removing
uvcdynctrl-data solved my problem (
sudo apt remove libwebcam0 uvcdynctrl uvcdynctrl-data).
I hope this blog post can help other people avoid spending time on google to solve the same 11-year-old problem…