Screen dims and goes to standby if multithread mode in KDE

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

As per my last comments to issue #7472 I found that with the setting video_threaded = "true" option retroarch doesn't prevent screen dimming anymore.

Expected behavior

Screen dimming prevention should be unaffected by the video threaded setting.

Actual behavior

Screen dimming is affected by the video threaded setting being set to true.

Steps to reproduce the bug

1. Open retroarch and make sure video threading is disabled
2. Looking at you power management plasma widget, make sure you see a message like "retroarch is preventing power management for the screen" - this is the correct behaviour
3. In retroarch enable threaded video
4. Observe how the message from the plasma widget has disappeared

Version/Commit

You can find this information under Information/System Information

• RetroArch: [version/commit]

games-emulation/retroarch-1.8.5

• OS: Gentoo Linux
• Compiler: x86_64-pc-linux-gnu-8.3.0

Start by reproducing the KDE Plasma power-management behavior with video_threaded disabled and enabled, using the reported RetroArch 1.8.5 environment as a reference. Trace the code responsible for preventing screen dimming and compare how that path behaves when threaded video is enabled. Done means the prevention message remains active in both modes, with a regression test if the existing test structure supports it.