Hello guys. You saved me a couple times, and seems like I need your help again.
Asus AMD R9 380 Strix
LG Ultrawide connected with DP
Samsung 5:4 connected with VGA and passive DVI-I dongle.
After successful Linux home server setup I’ve decided to go full open-source and installed Debian 9.5 with KDE on my main system alongside Windows 10, but had not very much luck with GPU drivers. After some testing with out-of-the-box 4.9 kernel and AMD driver from repository I got system that detects both my monitors, actually shows picture on both of them, but had a problem. Startup took ages. Like turn on - wait 5 minutes - here comes TTY login screen - another couple minutes - yay, KDE Plasma login screen. Enter password, wait for about 1 more minute, and here is my working dual-screen desktop.
I installed kernel 4.18.smth from backports (latest available), it fixed long startup completely. But now I have only one monitor actually working, other one is detected, OS says it’s being used, some windows open there, but in reality it-s blank with blinking in standby power LED. Same deal with proprietary drivers and open ones.
I moved to KUbuntu (I personally think default Ubuntu’s Unity desktop is ugly), same here with any kernel from 4.15 to 4.19.1 (current).
So now I am on Kubuntu (decided to stay for better third-party apps support, no distro can match Ubuntu in this, I think), kernel 4.19.1, built-in GPU drivers, only main screen is working. Googling gave me several similar topics across the internet, but none of them really helped me. Can some of you, probably?
I am still pretty noobish in linux, please ask for any logs, but also suggest where to find them.