Shell – Prevent monitors from going to sleep in lock screen on GNOME

displayportfedoragnomegnome-shellgnome3

I have two monitors running on my Fedora 22 machine, however due to this bug sometimes the second monitor will not wake up after the computer goes to sleep, requiring me to unplug the DisplayPort cable and plug it back it after a few seconds.

I can set GNOME to never put my screens to sleep, however I cannot simply leave my computer unlocked all of the time when I'm not at my desk, so I'm curious if I can have my computer be locked, but the screens not go to sleep?

I'm using Fedora Workstation 22 with GNOME Shell 3.16.2.

Best Answer

One solution is to use slock (apt-get install suckless-tools) which does not put the display to sleep. You'll need xautolock if you want to run it automatically.

Related Solutions

Monitor connected via displayport to DVI adapter won’t sleep properly

Same issue reported in nVidia Linux forum (Concerning DP backlight stays on after DPMS power save signal)

DPMS not working on GTX980 with DisplayPort connection
They mention some exact releases those are not affected or already fixed.

346.96, 352.63, 358.16

Linux – Stop display settings changing when turning off DP monitors on Linux Mint

In most cases, the RandR extension is used to configure display settings. Therefore, I will focus on it in this answer. So this answer may not apply if you're using Wayland, the proprietary NVIDIA drivers without DRM (Direct Rendering Manager) kernel mode setting enabled or have disabled the RandR extensions. If so, calling xrandr should result in an error instead of printing the current display configuration.

While xrandr does not change the display configuration if you unplug a monitor, your desktop environment does this. Technically, the desktop environment is implementing an xrandr client which is handling the XRRScreenChangeNotify event and updating your display configuration when a monitor is disconnected.

Depending on your used desktop environment, you can disable this behavior:

Gnome till 3.1.3:

gsettings set org.gnome.settings-daemon.plugins.xrandr active false

This option was to be removed in newer versions. Seems to be handled by Mutter now.

Cinnamon:

Copy /etc/xdg/autostart/cinnamon-settings-daemon-xrandr.desktop to $HOME/.config/autostart. Then append the line Hidden=true to the copied file.

Cinnamon before 3.4:

gsettings set org.cinnamon.settings-daemon.plugins.xrandr active false

Mate Desktop:

gsettings set org.mate.settings-daemon.plugins.xrandr active false

KDE

kscreen is managing the display settings in the KDE Plasma 5 desktop. There seems to be no way to disable the auto-plug behavior with a configuration setting. However, you can kill the daemon which is responsible for it /usr/lib/kf5/kscreen_backend_launcher to prevent any further changes to your display configuration. Note: The daemon will be restarted when you're launching the KDE display settings.

Best Answer

Related Solutions

Monitor connected via displayport to DVI adapter won’t sleep properly

Linux – Stop display settings changing when turning off DP monitors on Linux Mint

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