Second Monitor Doesn't Wake Up - Using DP to HDMI Adapter

[Appletax]

Got a computer that's main monitor turns on always as it should, but the second monitor does not, maybe because it's using a DisplayPort to HDMI adapter.

I set up four identical computers all with the same monitor. They all work beautifully except the one computer that has dual monitors. The desktop PC has one HDMI 2.1 (crappy TMDS) port and (2) DisplayPorts. All of the monitors are plugged into the HDMI port using Anker certified HDMI 2.1 cables. The monitors do not have a regular full-size DisplayPort, although they do have a USB-C-DP port. For the second monitor, I used a Plugable DisplayPort to HDMI adapter to output DisplayPort to the HDMI port on the monitor. I have used 30+ of them thus far with no issues.

The second monitor usually won't turn on when restarting the PC nor when waking it up. I unplug the adapter and plug it back in and it works. I put it in high performance mode, which switched off the Link State Power Management. Tried connecting the other monitor to the adapter. Nothing helps.

Why does the second monitor have these issues? Would all DisplayPort to HDMI adapters give me this issue?

The monitors have a USB-C-DP port, so I could try connecting a DisplayPort to USB-C-DP, which would need to be bi-directional.

Desktop PC = Lenovo ThinkCentre M70q Gen 4 Mini

- Win 11 Pro 24H2 fresh, vanilla install

Monitor = Dell 27 Inch 4K 60Hz [Model S2722QC]

DP to HDMI adapter = Plugable active adapter

 

[HCHTech]

It sounds like a problem with the MB's graphics - driver or BIOS update maybe? Can you daisy-chain the monitors? Do the monitors work if you connect them with regular DP cables?

 

[Appletax]

It sounds like a problem with the MB's graphics - driver or BIOS update maybe? Can you daisy-chain the monitors? Do the monitors work if you connect them with regular DP cables?

It's a brand new computer with a 13th Gen i5 with the latest drivers and BIOS. I see that as a common suggested potential problem, but I don't think that's the issue. The monitors don't have a standard DisplayPort, but rather a USB-C DisplayPort.

I have never daisy chained monitors. That's cool. It does not work over HDMI, which is how the main monitor is connected to the PC. The two monitors have a USB-C DisplayPort 1.4, so they can be plugged into each other and share the HDMI connection - not sure if that would work. Wonder if that can handle two 4K 60Hz monitors.

 

[nlinecomputers]

Why aren’t you using DP to USB C cables?

 

[frase]

I used a Plugable DisplayPort to HDMI adapter to output DisplayPort to the HDMI port on the monitor. I have used 30+ of them thus far with no issues.

I try to avoid adapters, I understand this is an active one though still can be hit and miss. This may be the issue as the monitor is not receiving enough power.

 

[Sky-Knight]

You don't need an "Active" adapter for HDMI -> Display Port, or Display Port -> HDMI.

You however... will note what I just said.

Because those cables are DIRECTIONAL, you can't "reverse" them, they won't work!

 

[Diggs]

Can you daisy-chain the monitors?

I thought the monitors themselves had to support daisy-change configuration? Meaning dual DP ports and monitor firmware. But, it's been a while since I've been down that road.

 

[HCHTech]

I thought the monitors themselves had to support daisy-change configuration?

I believe that's true, although I always use regular cables to drive multi-monitor setups. Daisy chaining just doesn't strike me as a robust setup, so I tend to avoid it to lower future support issues. I could be wrong, of course. In this case, if the computer has 2 DP ports and 1 HDMI port, then I would use two DP monitors for a dual-monitor setup. If the OP is trying to use the client's existing monitors with new computers, that might explain why they are trying to use adapters. Troubleshooting that setup certainly chips away at the savings gained by not buying monitors.