Repeating this problem from MikeDSM: HP USB-C Dock G5 - Display(s) Randomly Flashing

[JWFus]

Brand new HP EliteBook 640 G9, freshly imaged, new HP G5 dock, both fully updated software/firmware, Windows 10 22H2 64bit.  Multiple of these laptops experiencing displays randomly flashing as MikeDSM described in his post, which many people "me too'd" it.  Does anyone have the answer to the problem? 

[Jupitero]

Hello.

I recommend opening a support case with HP.

Can you mitigate the problem by using only HDMI, for example?

[JWFus]

On one users computer, I tried many (all) different cable combos into the G5 dock, but ultimately, you can only use 1 HDMI, the other has to be DP, and we don't have any bidirectional DP to HDMI cables.  With users busy schedules and most working from home a good percentage of the time, it's difficult to test every little change.  One guys setup has a 32" monitor and a 24", he said HP updates lessened but did not fix the problem.  I tried a different, brand new 840 G9 on his dock, and at least for the 5 minutes that I was there testing, that one did not have the problem.  Other users state it's pretty random - might work fine for several days, then acts up.  When I discussed the issue with an HP tech, he recommended modifying the bios - Advanced, Built-in Device options, change video memory size from 64 to something higher.  I haven't had a chance to change this on anyone's yet.

[Jupitero]

Hi.

If the BIOS settings have any or no effect, please post an update regardless. Try convincing the HP support person to send another dock to ease the troubleshooting if it doesn't help.

Regarding DP and HDMI - the cables are always unidirectional, e.g. DP to HDMI or HDMI to DP. How to identify:

HDMI-to-DP cables are more expensive due to active signal conversion and they have and extra USB cable for the power required.

Regular DP to HDMI cables do not require extra power. (except for long cables (over 5m or so) - then they are called 'active' cables.

[JWFus]

One user stated the BIOS mod did not fix the problem.

Another user felt the problem was her monitor so she swapped her Dell 19" with a newer Dell 24" and she feels the problem is resolved.  I will see if I can duplicate the problem on a similar 840 G9 and G5 dock with her old monitor when I receive it.