*Completely* turning off a display - laptop in particular

[britechguy]

Over the years there have been a number of different laptops that would allow turning off the display, including the backlighting, via a keyboard command. For blind users, this not only helped to ensure privacy, since they can never know who might be looking over their shoulders if using the computer in public, but also results in a significant extension of functional battery life since the display is one of the larger power consumers.

Is there a way to accomplish this, both turning off and later turning on again, via either Command Prompt BAT scripts or PowerShell PS1?

 

[Sky-Knight]

The best idea I have is the use of a dummy display blank, and then configuring windows to only display on that screen.

So plugin something like this: https://www.amazon.com/Headless-Display-Emulator-Headless-1920x1080-Generation/dp/B06XT1Z9TF

Then do this: https://support.lenovo.com/us/en/so...-while-using-external-monitor-ideapad-windows

If you need local access, unplugging the HDMI dongle will enable the local screen. Remote support software wouldn't care either way.

 

[britechguy]

@Sky-Knight

Thanks very much for the suggestion.

I am hoping that there is a way to emulate, programmatically, what used to be available on a number of laptops in the form of a "turn display off/on" key. If you hit that, the display would remain off until/unless you hit it again to toggle (or, in some cases, restarted the machine). If it was possible that way I have to believe there is a way to do it.

I also found one of Nir Sofer's utilities, nircmd, that allows toggling the monitor on/off but I don't know if it persists. Some of these things turn the monitor off until the user does something, then it turns on again, which is not what I'm looking for.

I'd like to be able to disable the display and backlight, and have that change stick, until/unless the user issues a command/runs a script to toggle the monitor back on. It would be OK if a restart turned the monitor back on, but "fully persistent" would be ideal.

 

[MudRock]

If you used that dongle, Win+P would cycle display. I know I've had a virtual display adapter for headless before on a laptop, but that was a decade ago and can't find it...

Can't find one I was thinking, but check this: https://www.amyuni.com/forum/viewtopic.php?t=3030 -- There are CLI actions too.

 

[MudRock]

Wait, I had thought pop in my mind. This was a while ago, but the screen reader I knew of, used to blank the screen. I'd check that too.

 

[britechguy]

Wait, I had thought pop in my mind. This was a while ago, but the screen reader I knew of, used to blank the screen. I'd check that too.

Both JAWS and NVDA have a screen curtain feature, but I know that NVDA only turns off the display, not the backlighting also, and I believe JAWS is the same. Neither is needed, or desired, by quite a few blind users, particularly if they're using their laptops in public and having the screen reader output "piped to their ears" (regardless of exactly how that's being done).

Essentially, I'm trying to find a way to completely turn off the display and backlight that could be used on any machine you can think of and where once turned off it stays off unless either intentionally turned back on or the machine is restarted.

 

[MudRock]

Essentially, I'm trying to find a way to completely turn off the display and backlight that could be used on any machine you can think of and where once turned off it stays off unless either intentionally turned back on or the machine is restarted

Now I gotcha, makes sense.

I think the reality of this is, is that this will be strictly hardware dependant. I'm sure there could be ways to trigger it. Just goofing, I have 1 Dell laptop sitting here that if you take brightness to 0, it actually turns off the display. All other laptops, it stays on. I think the reason JAWS (This is the one I'm familiar with from the past) doesn't offer it, is because the reality is that I don't believe it is something you can do natively.

My idea would be, if you used the virtual display adapter I linked above, you could figure out how to enable/disable the real video driver (through key combination for example, and use AutoKeys or something to capture it.), but that does not guarantee display off either, but I know a lot more laptops won't power the display if no data from the video driver vs brightness to 0.

Try the brightness to 0 first; You can powershell that easily.

Skip method 1 and 2 (2 is essentially display sleep), here are 5 things you could try - I suspect these are monitor blanking, not backlight off:

7 Ways To Turn Off Windows 10 Laptop Screen

Want to save your Windows 10 laptop battery power? Here are 7 methods to turn off Windows 10 laptop screen without putting PC into sleep or closing lid.

www.intowindows.com

Final note: Took me 5 google pages to even find that. I wonder if it can be done if not native to the laptop.

 

[britechguy]

@MudRock,

Thanks much. I'll have a look when time allows.

 

[Sky-Knight]

In linux there's a command that does exactly what you want...

Sadly, in windows my efforts to find an equivalent have failed.

 

[britechguy]

In linux there's a command that does exactly what you want...

And that would be?

Some noodling around the web with that information for either a Power Shell or Command Prompt equivalent may eventually turn up something.

 

[Sky-Knight]

@britechguy Depends on if there's a GUI or not...

With GUI is:

xset -display :0 dpms force off

Then this to turn it back on:

xset -display :0 dpms force on

display:0 is the first display, so you'd have to iterate that number if you have more than 1 display.

If the system is console only, you have to install vbetool. Then it's

vbetool dpms off

and

vbetool dpms on

BUT, if your goal is console blanking on a timer... IE the "screen saver", that's actually a change to grub.

So you have to edit /etc/default/grub

Add this line to it... note the timer is in seconds to adjust to fit what you want.

GRUB_CMDLINE_LINUX_DEFAULT="quiet consoleblank=600"

Then you run update-grub to sink the settings into the boot config and reboot.

The above is a big deal when working with Debian 10/11 because it won't automatically disable the screen on the console anymore. This isn't a problem for VMs, but when you are trying to build a tiny physical server for something it's one more thing to remember.