3 - monitors setup

Elleni · Veteran Joined: 23 May 2006 Posts: 1270

Why in kde plasma monitor settings I see three monitors, but I only can activate two of them simoulaniously?

The gentoo box contains the following gpu:
http://www.club-3d.com/index.php/products/reader.en/product/radeon-r7-250-eyefinity-4.1604.html

In order to activate the tv - connected via mini displayport - hdmi adapter, I have to deactivate one of the two monitors. I am using the opensource radeon driver. Do I have to configure three monitor setup via xorg.conf file, and if so - how? For now I can only use dual monitor setup and activate 2 out of 3 screens.

eccerr0r · Posted: Sun Apr 09, 2017 12:17 am Post subject:

I have a hardware limitation on my Juniper but not sure if it's the same problem as your card.

The gist is that I can have no more than two DVI/HDMI displays connected on my three ported card - which has a DVI,HDMI, and a Displayport. I can have three displays if and only if I have one DVI, one HDMI, and one NATIVE Displayport. If I hook up the Displayport through an HDMI adapter, it will cause the card to disable one port which apparently does not happen if I had a native displayport monitor. You might have a similar issue - a hardware limitation.
_________________
Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching?

Elleni · Veteran Joined: 23 May 2006 Posts: 1270

Hi eccerr0r,

thanks for you comment. I come from trying with a gentoo livesystem and there it works, there I can have three monitor setup with all three enabled. So I guess it must be my installation / setup, that limits me somehow.

radio_flyer · Posted: Sun Apr 23, 2017 6:59 pm Post subject:

If you have Eyefinity and three outputs--HDI, DVI and Displayport--you should be good to go without any xorg.conf. I'm running three monitors with Plasma5 and the open-source radeon driver with no xorg.conf.

The KDE (Plasma5) panel settings are configured in $HOME/.config/plasma-org.kde.plasma.desktop-appletsrc. The screen settings are stored in $HOME/.local/share/kscreen in some bizarrely-named file. Try deleting the former and then reconfiguring your monitors. If the KDE panel is still bouncing around from monitor to monitor, try setting the latter bizarrely-named file read-only once the panel is on the correct monitor. That's how I finally got my setup to behave.

Worst-case, try the famous KDE fix-it-all approach: delete the $HOME/.kde subdirectory and let KDE rebuild it from scratch.