Resolution of 4K displays changes to 1024 X 768 when the display port goes to stand by or power off

Hi,

Thank you for writing to Microsoft Community Forums.

This happens when the monitor doesn’t power off completely and don’t send signal to Windows, that’s when Windows creates Simulated monitor with default resolution of 1024 X 768.

You can try changing the resolution from Registry and check if that helps in resolving the issue. Please follow the steps mentioned below to change the resolution from Registry:

Note:  Important this section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs.

Follow the steps to take backup of registry.  

1. Press and hold the Windows key + R, to open Run box.

2. Type regedit and click on OK.

3. Now, navigate to the location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration\

4. Expand the Simulated key, click on 00 key, and on the right pane change the value of PrimSurfSize.cx and PrimSurfSize.cy to your desired resolution.

5. Now, expand the first 00 key, click on the second 00 key, and on the right pane change the value of ActiveSize.cx and ActiveSize.cy to your desired resolution.

6. Restart your computer.

If changing the value to desired resolution didn’t help, please change the value to 1600 X 900 and check.

Hope it helps.

Please reply with the status of the issue, we will be glad to help you further.

Nikhar Khare

Microsoft Community - Moderator

• Now, navigate to the location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration\

• Expand the Simulated key, click on 00 key, and on the right pane change the value of PrimSurfSize.cx and PrimSurfSize.cy to your desired resolution.

• Now, expand the first 00 key, click on the second 00 key, and on the right pane change the value of ActiveSize.cx and ActiveSize.cy to your desired resolution.

Alas, I already tried

Okay, I'll be frank... I've tried that approach already, it does solve the resizing, however it still moves all my windows from my second display to my first (main) display.

It got me to realize something else I could try.

This solution should copy the entire default display configuration to the simulated profile. So the simulated profile also has a dual display configuration.

What I did

So here's what I did and I'm currently testing:

1. Opened regedit
2. I deleted ALL sub-key profiles in:
   • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration
   • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Connectivity
   • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\ScaleFactors
3. Restarted my computer and let Windows generate a clean list of profiles (this happens automatically)
4. Login to my profile
5. Reconfigure the positions of the screens, if necessary, I needed to drag my displays around in the config. (I won't go into this, since this is basic windows config)
6. Lock the computer with Windows key + L and wait for the screens to automatically go to standby-mode/off
7. Unlock the computer
   • At this point, all profiles necessary are automatically generated and all the unused profiles are gone. (older monitor setups)
8. I opened regedit
9. Right clicked on the sub-key from Configuration the with the longest name, in my case:
   • GSM5B0962772_0B_07E0_12+GSM5B0962811_0B_07E0_EB^B452151CA3D8558B6B63B3E0EA889B4A
   • This profile has 2 sub-keys as well 00 & 01, which represent 2 displays that's why I know, this is the key I need to copy.
   • The other profiles are used for start-up procedures, leave them untouched
10. Then I clicked Export and saved the file on the Desktop as monitors.reg (just easy to find and edit quickly)
11. Then I copied the name of the simulated profile (select profile key, press F2, CTRL+C and then ESC), in my case:
    • SIMULATED_10DE_1B81_00000001_00000000_1100^0BC5D99F3E51A707721027956C434484
12. I edit the monitors.reg file I saved earlier with a text editor that has a replace function, basically Notepad would suffice
13. Here I replaced everything
    • from:
      GSM5B0962772_0B_07E0_12+GSM5B0962811_0B_07E0_EB^B452151CA3D8558B6B63B3E0EA889B4A
    • to:
      SIMULATED_10DE_1B81_00000001_00000000_1100^0BC5D99F3E51A707721027956C434484
14. I saved and closed the monitors.reg file
15. Now in regedit I delete the simulated profile key
16. Double click the monitors.reg, so Windows will start importing the new values.
17. After that's done, restart Windows (very important step, in this case)

And you're done... It looks more complicated then it actually is, but it does seem to work perfectly (for now)

I will come back on this in a couple of days to share my experience.

Hi,

Thank you for replying.

Please keep us posted on the issue.

Nikhar Khare

Microsoft Community - Moderator

Please keep us posted on the issue.

It works...

but there are still some caveats

• Program windows that are "snapped" to a position on the display, e.g. 2nd display on the top left corner, are un-"snapped" and floating windows after coming out of standby. The windows are also relocated to the 1st display again, and warped back to it's original dimensions (w×h) before the window was snapped to the corner of the display.
• Since I implemented my solution, a few days later another mystery profile popped up in my registry.
• One time all screens where moved to the 1st display, I suspect this happened because there might have been a slight delay (a 10th of a second) that the 2nd display went into standby sooner. This might also explain the mystery profile, since a new display scenario automatically creates a new configuration profile in the registry.

It's still not perfect, but it works a lot better then before

In my opinion I still think Microsoft has to figure out a way to solve these issues, since the display port is basically mainstream for newer displays, and multi-monitor setups are pretty common. I've posted the same question in the past, perhaps in different words, but all I got in reply was that my graphics card driver is the issue. This is simply not the case, there's work to be done, and this should be fixed.

I hope this post can help others with similar issues

Okay, I'm now positively sure that the moving of the application windows from my 2nd display to my 1st display has to do with the order they wake up.

It's about a split second (but not always), but it's apparently enough to start re-arrange all my windows.

But mostly they do initialize together, then all is fine.

So then... what could be causing this delay?

Hi,

Thank you for replying.

As you have mentioned that the windows from the 2^nd display are moving to the 1^st display when the PC wakes up, I suggest you to try removing the hidden monitor drivers and see if that helps in resolving the issue. Please follow the steps mentioned below:

1. Press and hold the Windows + X key on the keyboard.

2. Select Device manager.

3. Click View tab.

4. Select Show hidden devices.

5. Expand Monitors and remove all the greyed out devices. To remove the greyed out devices, right click on the device and select uninstall.

6. Restart your computer.

Hope it helps.

Nikhar Khare

Microsoft Community - Moderator