External Monitor got disconnect while switching the display

[abhinaychaudhry]

Hi everyone,

I would really appreciate it if someone could help me with this issue. I've spent a lot of time troubleshooting it and haven't been able to find a solution.

I recently purchased a Portronics MPort Vault Pro docking station. Most of its features work correctly, but I'm facing two major issues with my HP ProBook 440 G8.

Issue 1: External monitor doesn't wake after sleep

When my laptop goes to sleep (or remains idle for around 15 minutes), the external monitor does not wake up when I press a key or move the mouse.

• The laptop screen wakes up normally.
• However, the monitor loses its connection over both HDMI and DisplayPort (via DP-to-HDMI adapter).
• The only way to get the monitor working again is to unplug the USB-C cable from the laptop and plug it back in.

---

Issue 2: Monitor disconnects while switching displays

Even when the laptop is not in sleep mode, if I switch displays using Win + P (for example, from the external monitor to the laptop display and then back), the external monitor disconnects.

Again, the only way to restore the display is to reconnect the dock.

Interestingly, when this happens:

• Most USB devices connected to the dock continue to work.
• Occasionally, even the USB-A ports stop responding until the dock is reconnected.

---

Troubleshooting already performed

I have tried almost everything I could think of, including:

• Updating BIOS
• Updating Intel graphics drivers
• Updating USB and chipset drivers
• Updating Windows
• Testing both HDMI and DisplayPort connections
• Reinstalling USB devices and monitor drivers

Unfortunately, none of these steps resolved the issue.

---

Additional observations

I also have access to an HP EliteBook 640 G11.

Using the same MPort Vault Pro dock with the G11:

• Everything works perfectly.
• The monitor wakes correctly after sleep.
• Display switching works normally.
• Monitor brightness can be controlled using DDC/CI.

I also own another USB-C dock (Wozoyo), and it works perfectly with my ProBook 440 G8, including stable monitor connectivity.

So the issue seems to occur only with the combination of the HP ProBook 440 G8 and the MPort Vault Pro dock.

---

Has anyone experienced a similar issue or found a solution?

Could this be related to:

• USB-C DisplayPort Alt Mode implementation?
• HP firmware/BIOS?
• USB power management?
• Intel graphics driver compatibility?

I'd really appreciate any suggestions before I end up buying another docking station, which I'd prefer to avoid.

Thank you in advance for your help!