miket
Guru
Joined: 28 Apr 2007
Posts: 488
Location: Gainesville, FL, USA
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 Posted: Fri Sep 23, 2022 4:31 pm Post subject: KDE / QEMU / SDL -- no host screen blanking |
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When I run a guest VM under QEMU with an SDL window on my KDE desktop, something disables screen blanking on the host. Yes, there are cases when that always-on mode can be useful, but most of the time that is an annoyance for me.
I was hoping there was a not-well-documented disable/enable-screen-blanking QEMU setting that I'd missed. One thing I've found so far is the reason that the screen blanker is disabled. | http://wiki.libsdl.org/FAQUsingSDL wrote: | Why does SDL disable my screensaver by default?
Many applications using SDL are games or screensavers or media players where the user is either watching something for an extended period of time or using joystick input which generally does not prevent the screensaver from kicking on. |
It goes on to say that I can enable screen blanking by use of the SDL_VIDEO_ALLOW_SCREENSAVER environment variable. Libsdl exposes an SDL_DisableScreenSaver() function, but the QEMU-7.0.0 sources do not reference it.
So libsdl2 does expose some hooks, but they can't help me change the screen-blanking behavior of a running QEMU instance. I went to the QEMU bug tracker to see if anyone had requested a configure-SDL-screen-blanking feature--but for some reason they set up their bug tracker to require that I be signed in to search using a specific search term. Grr.
Yes, the SDL_VIDEO_ALLOW_SCREENSAVER=1 trick works, but having a setting that could change the behavior of a running instance would be better. Hmm--this comes just when I was rejoicing that I no longer had to set environment variables when starting QEMU.
So there. Is there a better way you can suggest? Should I file a bug with QEMU? |
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