Gnome Shell 3.16 - Dim Screen When Inactive- Not Working

[w201]

Hi- so under Gnome Power Saving, one of the options is dim screen when inactive, however the system is not detecting idle time, becuase eventhough I have it set for 5 mintues, the screen never actually goes dim. Other features like suspend on lid close, and screen brightness adjustment work great.

I don't use a login manager like GDM, so I don't know if that's something that's necessary, or If I need an ACPI rule (figured Gnome had that sorted out). Anyway, any ideas?

Thanks

[dino99]

that works with some hardwares, and not with many others; this is quietly fixed either into the kernel and/or into the graphic stack

[w201]

I believe I'm set at the kernel level, but what do you mean by the graphic stack, any examples?