Is there a way for the hdmi output to completely turn off. When I leave my pi idle the screen turns black but the screen stays on and never turns off. The monitor turns to off/idle with other computers but it doesn't with the pi, just turns black.
Take a look at this blog post.
According to the author, the kernel framebuffer driver does not have complete power management support. Perhaps future versions of the Raspbian kernel will contain a fix. Until then, the author provides a workaround script that polls to see whether the screen should be off or on and runs
tvservice --off or
tvservice --preferred as appropriate.
I think it depends on your Linux distribution. Tv screen should turn off when raspberry will stop send signal.
On the other hand I discover that when I turn on screen after run pi it does not connect to each other. This issue looks like firmware stuff and there is no solution fot this now.
In current firmware you can to turn the monitor off and on with the folowing:
sudo vcgencmd display_power 0
sudo vcgencmd display_power 1
It does not risk changing resolution, and there is no need for fbset, chvt, xrefresh, or restarting your GLES and OMX overlays afterwards.
I've tested it on my Raspberry Pi 3
You can also try adding the line
hdmi_blanking=1 to /boot/config.txt. It automatically turns off the monitor or TV when the pi blanks the screen. It's not yet implemented on the RPi4, although it works on all previous generations of Raspberry Pis. Video Options