Acer KG251Q M3: DisplayPort cable has to be unplugged/replugged to get signal

KP69

I have an Acer KG251Q M3biip monitor and an ASRock Challenger D (RX6600 CLD 8G) video card. When I connect the monitor to the card with a DisplayPort cable, it only works the first time after plugging it in. After turning the computer and monitor off, then turning them on again, the monitor gets no signal. But if I unplug the cable and plug it back in again, it will work until the next time I turn the computer off. If I use an HDMI cable to connect the monitor to the video card it works as it should. What could be the reason that the DisplayPort cable has to be unplugged each time in order to get a signal to the monitor? The DisplayPort cable I'm using works fine with other monitors with this same computer.

GAMING6698

https://community.acer.com/en/discussion/708484/acer-kg251q-m3-displayport-cable-has-to-be-unplugged-replugged-to-get-signal

The issue you're experiencing with your Acer KG251Q monitor and ASRock Challenger D RX6600 graphics card seems to be related to a common problem known as "DisplayPort not waking from sleep" or "DisplayPort no signal on wake."

Here are a few potential reasons and solutions:

1. Firmware/Driver Issue: Ensure that your graphics card drivers and monitor firmware are up to date. Sometimes, outdated drivers or firmware can cause compatibility issues that result in DisplayPort problems.
2. Monitor Settings: Check if there are any specific settings on your monitor related to DisplayPort. Some monitors have options to adjust the input signal detection or power management. Adjusting these settings might help.
3. Graphics Card Settings: In your graphics card control panel (such as AMD Radeon Software), check if there are any settings related to power saving or display output that might affect DisplayPort stability.
4. BIOS/UEFI Settings: Occasionally, BIOS or UEFI settings related to power management can affect DisplayPort behavior. Check if there are any relevant settings and consider updating your BIOS/UEFI to the latest version if possible.
5. Cable Quality: While you mentioned that the DisplayPort cable works fine with other monitors, sometimes there can still be compatibility issues with specific combinations of graphics cards and monitors. Try using a different DisplayPort cable if available, preferably one that is certified for DisplayPort 1.2 or higher.
6. Monitor Sleep Settings: Adjust the sleep settings on your monitor. Sometimes, if the monitor goes into a deep sleep mode, it may not wake up properly when the computer is turned back on. Experiment with different sleep settings or disable deep sleep mode if possible.
7. Power Cycling Sequence: When turning on your computer and monitor, try a specific sequence: turn on the monitor first, wait a few seconds, and then turn on the computer. This sequence sometimes helps with DisplayPort detection.
8. Windows Power Options: In Windows settings, under Power Options, check if there are any settings related to PCI Express or graphics card power saving features. Adjusting these settings might improve stability.

Given that HDMI works fine but DisplayPort doesn't after the system is turned off and on, it strongly suggests a handshake or detection issue with DisplayPort specifically. Start with updating drivers and firmware, checking settings.