I have a laptop running Windows 11. It is connected, through a dock, to two monitors.
When the laptop is left unused for a little while, it turns off the monitors. If I then move the mouse or press a key, it turns them on again and may or may not also require me to re-authenticate myself.
All of the above is as it should be. But every now and then -- maybe 5-10% of the time? -- one of the monitors doesn't come on again. It isn't always the same one. I don't remember whether I've ever seen both of them have the problem at once.
In this situation,
- the monitor claims to be receiving no video signal;
- the laptop claims that the monitor is attached and seems not to notice that anything is amiss.
I have not noticed any particular pattern to when it goes wrong.
The machine is configured never to go to sleep when on mains power, and is more or less always on mains power. (Hence, this is happening when it has turned the monitors off but not put itself to sleep.)
When this happens, I can reliably get everything working again by disconnecting and reconnecting the monitor's power supply. Disconnecting the video cable and reconnecting it doesn't help.
Specific hardware:
- laptop is an HP ZBook Fury 16 G9
- dock is a Dell Dock WD19 (I think a colleague of mine has had similar problems with similar hardware and reported that switching to a different dock didn't fix them)
- monitors are HP U28
- dock is connected to laptop via USB-C
- monitors are connected to dock via DisplayPort (I do not remember for sure whether I have tried using HDMI instead, but the dock has only one HDMI port and two DP ones)
- monitors are running at 3840x2160.
I haven't tried connecting a monitor directly to the laptop and seeing whether it exhibits the same problem. I haven't tried connecting through the dock but using only a single monitor. (I would find it very inconvenient to do without the second external monitor, and would rather have this problem intermittently with two monitors than not have it with one. But if something like this would give information that might lead to a fix, I can try it.)
I have had the laptop for quite some time and the problem has persisted across updates of Windows, of various drivers, etc. The laptop is kept well up to date. It is managed by my employer and I unfortunately cannot do things like switching between driver versions.
What is likely to be going wrong? What if anything should I do to diagnose it and/or fix it?