The original post: /r/debian by /u/maw_walker42 on 2025-01-30 13:56:19.

Kind of Debian related in that I was using Debian when this happened. Debian was not at fault however, as we shall see…I have a Dell 34" Ultrasharp monitor I have used for years. It’s been hooked to a couple GPUs: AMD RX580 and currently an AMD RX 5700 XT. I have used the display port input for years, on FreeBSD, Linux, Windows, zero issues, well, not zero but that’s another story. My Debian Gnome desktop started dimming randomly but frequently, then return to full brightness.

Stupid me thought it might be Gnome so installed KDE, same behavior, plus now when rebooting only, not cold starting, the display would go into power save mode and I would never get a desktop. I thought there might be a bug somewhere because I am using testing (Trixie). Let’s try Pop_OS!, nope, same, Ubuntu, same, Endeavor, same, at midnight I gave up and hit the bed. This is why it pays to have a separate /home.

Last night my brain came up with “what if it’s the cable”? So, this morning I swapped the HDMI input from my work laptop to my Linux box, used the thunderbolt from my old Mac mini for my work laptop and I’ll be damned if it didn’t;'t work fine.

So, for whatever reason, DisplayPort was causing the dimming issue at the desktop and when booting (rebooting), it just lost the signal entirely. From here on out it’s HDMI for me…

Also, not a fan of Endeavor. I used Arch for a long time years ago, but after work today I am going back to Debian.