Windows 10: Switching into a fullscreen game appears to switch HDR off, which causes a black screen for...

I've recently seemingly out of nowhere, no idea what could've caused it started getting this issue where some fullscreen games make my monitor go black for a while when tabbing into or out of them. I've noticed that my display does say it's going to "DisplayPort1" when tabbing into them, and "DisplayPort1 HDR" when tabbing out both indications only showing up after the black screen, of course. Sometimes, tabbing in or out seems to mess up the colour settings until I switch again.It doesn't seem to happen with every game? but that might have to do with some of them being fullscreen border

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Unable to switch HDR colour on .

Unable to switch HDR colour on .. tower PC .. windows 10 pro regularly updated.. version 20H2 os build..19042.1288 monitor LG 55in tv resolution 4096x2160 (hdr compatible) On diplay settings page.. use HDR toggle switch is set to off.. (not greyed out).. When I click to on.. the screen goes black for 1 second then as the picture reappears.. I see the toggle switch back to off.. I have checked the DXDIAG log and HDR is ok.. (log attached) and in the registry (video settings) value 1 Any suggestions anyone? Thanks Konnie ..

 

HDR-capable monitor becomes completely unresponsive when switching between SDR and HDR under certain conditions

I have the Alienware AW3423DW in HDR Peak 1000 mode. Here are the steps to replicate the issue:

The relevant system information is as follows:

• Windows 10 version 21H2
  
• Nvidia GPU with GeForce Game Ready Driver version 528.02
  

1. Power on computer with HDR already enabled in Windows settings from previous session. The computer will start in SDR mode but will switch to HDR as soon as it reaches the lock screen.

2. Launch an application that does not natively support HDR but which runs in exclusive fullscreen (e.g. a non-HDR supported game).

3. Tab out of the game and switch off HDR in Windows settings.

4. Monitor switches off and is completely unresponsive, after a few seconds the Windows "device disconnected" sound effect can be heard.

5. At this point, the only way to restore the monitor is to unplug and replug the power cable of the monitor. Restarting the PC or unplugging and replugging the display cable does not work.

This is how I have manually recreated the issue, but the way it has happened to me most often is by simply alt-tabbing out of an application while running in HDR mode. If the application being tabbed out from is particularly resource-demanding and results in the monitor spending a long time switching between HDR and SDR, then it will completely fail and switch off, becoming unusable.

I have already tried reinstalling my graphics driver which did not help. How can I determine which component (i.e. Operating system, GPU, Monitor) is the point of failure that is causing this problem?

 

Windows 10 forcing HDR on Exclusive Fullscreen

Just noticed recently that if I have HDR enable, Windows 10 will try and force HDR on every game if its set to Exclusive Full screen regardless if the game supports HDR or not. This normally results in a terrible image for games that dont support HDR. The only fix seems to be disabling HDR in Windows 10 or switching the game to borderless fullscreen. Noticed this seems to be a recent issue and wondered if its caused by a recent Windows 10 Update and/or Nvidia drive update??