I am a Linux newbie and have found this site many times in various searches for various things I needed to learn. This is my first post. I have searched for hours and just can't find what I need. Hoping someone here can help.

I can give specific information about my hardware, but I really don't think it is specific to my hardware, I think it is a problem with my setup. I only have one monitor and it is a 4K TV hooked up with an HDMI cable to my GeForce GTX 970 graphics card. I have everything setup and working correctly and it is beautiful. My problem is that I like to leave my computer on all the time and turn off my monitor when I'm not actually using my computer. When I turn on the monitor again, I only see a message from my TV saying there is no signal. Even if I just turn off my TV and turn it right back on. No matter what combination of buttons or mouse moves I made, nothing comes back. I have no idea if it is sleeping or locked or what, I can't see anything.

I have this computer setup to dual boot to Windows 7 Pro and it doesn't like me turning off the TV either. However, I have a visible screen when I come back to Windows. The problem there is that it takes any open windows and icons and shoves them all to the upper left corner of my screen.

I think both Linux and Windows thinks the normally "secondary" screen was taken away and tries to default back to the "normal" DVI monitor, which isn't there. I know more people are starting to use this setup instead of an actual computer monitor and I can't can't believe I'm the only one with this problem, but I have searched way too long and found nothing. Please help if you can. I am using Linux Mint 17.2, in case that helps tell me which setting needs to be changed.

Thanks!

The HDMI signal is being cut off because there is no return signal when you turn off the TV. It should return when you press a key or move the mouse, but I'm not sure how Mint configures this. I use Debian with Xfce, and moving the mouse or pressing the shift key wakes it up and restores the monitor. I generally turn my monitor off at night to save just a little electricity, and have no other issues. Without knowing your hardware and DE, it's hard for anyone to give you any specific advice. You might try the power settings in Mint to see if you can get any improvement.

If you are doing power management manually, you might want to disable it before you do.

$ xset -dpms s noblank s noexpose

Otherwise moving the mouse or keyboard strokes should return the signal. Although nVidia drivers might be buggy. Restarting X should recover (or rebooting) if it doesn't recover like it's supposed to. Shifting between a console and back can sometimes force it to correct. Cntrl+Alt+F2 then Cntrl+Alt+F1 (or F7 depending on distro and age).

I appreciate the inputs. Moving the mouse and touching random keys wasn't working, already tried that. The CTRL+ALT+F7 was the key to helping me find what works for my distribution. Again, I'm on Linux Mint 17.2. To get my GUI back, I have to hit the following keys:

CTRL+ALT+F1
ALT+F8
CTRL+ALT+F1
ALT+F8

No idea why I have to go through it twice, but that is the only thing that seemed to work after testing many combinations. The first CTRL+ALT+F1 does bring up the terminal one screen that I can interact with. The first ALT+F8, takes it back to no signal. CTRL+ALT+F1 the second time brings the terminal one screen again. Finally, the second ALT+F8 brings back my GUI screen the way I left it. So this will fix my issue and it is much appreciated.

From what I read, the ALT+F8 should work, but for whatever reason doesn't. That would be easier, but this works just fine.

Thanks again!

The Alt+F# varies depending on setup. Before systemd you could comment out a few TTYs in /etc/inittab and doing that lowered the F# for X. And various other ways to configure a system. In either case, your display is about to fail by the sounds of it. So be prepared for WHEN that happens. Or just replace the display with a good one and watch that issue magically disappear entirely.

Just random thoughts. Could there be power saving features in the monitor that would do just as good as turning off. Generally turning off isn't really turning off.

I hope this isn't true since I'm dealing with all brand new hardware. First time I finally did the build your own computer. Went near top of the line on everything I purchased for this setup, including the 4K TV as a monitor.

That is a good tip, I briefly checked and couldn't find anything except when no signal is coming to it because you are listening to music. I will check this possibility out more.

While I'm glad I figured out how to get my screen back, it isn't quite working like I wanted yet. I just had a couple of browser windows opened yesterday while testing if things were the way I left them. Tonight, I had a VirtualBox virtual machine open and when I came back, it was closed and showed that it had aborted. That is definitely not what I expected. I want things just like I left them, just like they would be if I had a regular monitor connected through the regular DVI or VGA cable. For many years now, hooking up my TV as a second screen through HDMI has done funky things to my desktop icons and open windows. I know this is the problem, I just don't know which setting to mess with to make the OS not look for feedback that something is connected regardless of it being turned on or off. Honestly, I have no idea why this was changed when HDMI came along anyway. VGA ports worked one way and then DVI came along and worked the same way, then HDMI came and for whatever reason wasn't treated the same. I am a big believer in "if it ain't broke, don't fix it". The search continues...

It just seems oddly similar to an older display my mom had on her computer with nVidia GPU. Had to flop video modes a few times to get it to be visible. The number of times got progressively worse, and ultimately it stayed black. It was a 5+ year old display. Still a 4:3 LCD style monitor with VGA connector. Perhaps it was an nVidia driver issue, I never really tried it on other machines. But a new display that replaced it made the issue go away. I had another display go south about the same time, so it might have been some lightning spikes that pushed them over the edge. For my display, it would wash out completely white after a short usage period and I figured I needed a new GPU, but it was the display. Although that GPU did fail within a year of the display replacement.

Instead of ALT+F8 how about ALT+F7?

Might save you an extra step.

On most systems, ctrl-alt-F7 is the tty running X. After you get the terminal, try using that instead of Alt-F8. Ctrl-Alt-F(anything but F7) should give you a terminal, and Ctrl-Alt-F7 from there should give you your normal desktop back. No guarantees, I don't run Mint, but it should be worth a try.

ALT+F7 was one of the first things I tried since that was part of the original suggestion. It seems this is reserved for something else in Linux Mint 17.2. It does get me a terminal looking screen, but says..

* speech-dispatcher disabled; edit /etc/default/speech-dispatcher
Starting VirtualBox kernel modules ...done.
* VitualBox Additions disabled, not in a Virtual Machine
saned disabled; edit /etc/default/saned
* Restoring resolver state... [ ok ]

Trust me when I said that I've tried many combinations. If you think about the solution I found, going through a certain combination twice, shows I had to have tried tons of things to figure out that one worked. I do appreciate the attempts anyway. This works for me for now, hitting a few keys isn't too painful.

Really wish I could get it to stop reacting to my monitor being turned off, because that is the real problem, especially since I now know it is going to close my virtual machines. This entire setup was to run virtual machines. Not planning to do anything on the host, not even a web search, just open VirtualBox and my virtual machines. Maybe when I learn more about Linux and can have a minimal host running, this problem will go away if I haven't figured it out before then.

Thanks again for the inputs.

Are you that desperate to save a little electricity? You can't just leave the TV on? It has no standby capability? If that's the case, I guess you'll have to live with the current situation. Or else switch to a better distro. There are many, many from which to choose.

Desperate to save electricity? No. I also don't see the point in just pissing away electricity, plus it is a 43 inch screen that lights up the entire room, why would I want to leave that on? I asked a question hoping someone would have said, "all you have to do is XYZ". Haven't you ever wanted to do something and didn't know how, so you asked a question? Why come asking if I'm that desperate? If you didn't have an answer to the question, why not just move along.

Did you even try using "xset -dpms s noblank s noexpose" (post #5 in this thread) ? It disables the display power management system. And otherwise tells X to not hide apps and to not hide your desktop after a timeout period. Since you're effectively doing this anyway when you push the power button. You might also need to stop the xscreensaver if it's installed, and if it's running. The [no]blank period is when the screensaver typically kicks in. The [no]expose period is when even the screensaver goes black. Or something like that as I might have those flip flopped.

There is literally no feature in linux or any other OS to do what you want if it's hardware related. At least not until the hardware is changed. Any ati/amd GPUs laying around?

There are remote options which might keep you from killing your vm's from modeswitching. Like x11vnc + vncviewer or x2go or other gui ssh type options. There might be ways with xrandr to change the mode in X instead of jumping to consoles and back to X. Which is why I mention the remote X session route.

$ xrandr
(gives some available modes)

for my current external display:
$ xrandr --output HDMI1 --mode 1280x720 --panning 1920x1080

$ xrandr --output HDMI1 --mode 1920x1080 -- panning 1920x1080
(sort of a poor mans zoom without rearranging your apps on your display)

I sometimes need to do this for more wiggle room when running from the native LCD of my laptop as 1366x768 isn't big enough for some modern apps. The intel GPU on this laptop lets me go up to 4k x 4k. You just have to wiggle the mouse around to see the off screen parts.

$ xrandr --output eDP1 --mode 1366x768 --panning 4096x4096

Lot of options in linux. Given a certain amount of hardware / driver support.

Yes I did try to XSET suggestion you gave. As far as I can tell, nothing changed after I made those changes. I even read through some of the other options on that command to see if there was anything else that might help. Nothing stuck out to me, so I just moved on to the next suggestions. Having a few days pass now, my VMs don't always get aborted. I haven't figured out what makes them do that or what makes them stay alive.

About the remote suggestion, I definitely want to get to that level of knowledge, but it is beyond my current abilities. I went to the xrandr website and that looks promising. I don't have much time right this minute to read all that, but plan to come back and read through more of it to see if I can find what I'm looking for.