Did not detect any DDC-compatible displays about display-switch

[haimgel]

Hello, thanks for the detailed report! I'd suggest:

1. Check the Linux-specific config, see the project's README. You need to add your user to a certain group, or run it as root to be able to communicate via DDC.
2. See if the issue with your hardware, or with this app specifically. I'd recommend using ddcutil to query your DDC devices, and see if it can see them or not. E.g. ddcutil detect. See here for more examples.

[bigfoote]

Success! ddcutil confirmed that both monitors are indeed DDC devices, so it made sense that following your instructions in point #1 got everything working. I just didn't realize that setting it up as a service included getting the permissions the way they need to be even if just running it myself. Not sure if there's any way to add a log message if access is denied to that directory.

[bigfoote]

Hmmm...my setup had been stable for over a year, and suddenly I started getting this problem again. I checked that my user is in fact in the group i2c and that my monitors (at /dev/i2c-4 and /dev/i2c-5) have the correct permissions (crw-rw---- 1 root i2c...), and running display-switch as root doesn't solve the problem. Any ideas?! I wonder if something changed in the Nvidia driver so that the monitors no longer are showing up as DDC-enabled, but 'ddcutil detect' still finds them...

[bigfoote]

Swapped my Nvidia card for an AMD one, and the problem went away. I don't know why, but closing for now.