Monitor will not go to sleep mode on Windows 11 avec AffichagePort or HDMI

Windows Client (10, 11, 12) Windows 11
1

I have a custom built Windows 11 computer which fails to put any monitor in sleep mode when the monitor is connected via DisplayPort or HDMI. The monitor turns off after the configured number of idle minutes, then it comes right back on after a second or two. This cycle will repeat continuously forever.

I tried 2 different GPUs (RTX 3070 and GTX1070) and 2 different monitors (Dell 27" QHD and Asus 27" QHD) and the behavior is the exact same as soon as any of the DP/HDMI port is used, in all possible combinations.

The only way the sleep mode behavior works fine is when using only the DVI port from the GTX1070. I tried both GPUs and both monitors on another Windows 10 computer and they work just fine and will go to normal sleep mode after the configured delay.

Given that all GPUs and monitors work as expected when paired with another computer, I suspect the issue would be from a Windows 11 configuration that would mess with DP/HDMI.

Searching online, I found many posts about a DP related issue that prevents monitors from getting out of sleep mode but nothing on my issue which is essentially the opposite.

Any idea welcome. Thanks.

2

The solution to this problem in my case was to disable the “NVIDIA High Definition Audio” from Windows Device Manager. This removes the audio output capability of the DP/HDMI ports on the GPU but the monitor sleep mode now works as expected.

For audio, I have the standard MB onboard audio and a PCI-e SB audio card so really I had no need for the audio through DP/HDMI. However I can see this being an issue for some people who are relying on this feature.