Keeping the Screen Turned off While Getting Inputs

Ahmad Nouralizadeh ahmadnouralizadeh at yahoo.com
Sat Aug 26 20:19:39 UTC 2023


 > > However, I would have expected that VLC would produce a lot
> > GPU/iGPU accesses even without drawing anything, because it would
> > try to use GPU decoder.
For the discrete GPU, the turned off screen requires much smaller bandwidth in any benchmark (reduces from 2GB/s to several KB/s). The same seems to be true with iGPU. Of course, there might exist some DRAM accesses originating from the GPU/iGPU. But the main traffic seems to fade. These assumptions are based on my experiments and I could be wrong.
(P.S.: VLC seems to be aware of the screen state. The rendering thread will stop when the screen is off (mentioned here:https://stackoverflow.com/q/76891645/6661026).)

> > Displaying video is also often done using GL or Xvideo - plain X is> > too slow for this.
I'm looking for a simpler solution. I'm not familiar with these Xorg-related concepts! It seems a bit strange that turning off screen requires so much effort! If `xset dpms force off` would not cause screen activation with user input or `xrandr --output...` wouldn't cause segfault, everything would be fine.

>edit to add: google suggests another candidate might be something
>called pin-instatPin works at the source code level. It counts source-level accesses which might not reach DRAM (e.g., services by caches).

> > best
> > 
> > Vladimir Dergachev  
  
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