Unresolved 2-3s blinking of external monitor at Dell E-Port Plus II Dock

Dear jphughan,

Many thanks for your helpful hint. Unfortunately, my system does not have an Intel U series processor, and as written in the KB article, Intel HQ processors do not have MST hubs. My system has an i7-6820HQ CPU.

Obviously, there seems to be a similar issue on HQ CPU systems, but unfortunately I can not find a fix?

We had this issue and it was resolved by a firmware update to the MST hub built into the system.  Go to support.dell.com, select your system, select Drivers and Downloads, and search "MST".  Note that sometimes if the OS selected by default there is the one you want, you have to choose some other OS and then switch back for anything to appear.  Anyway, the update you're looking for is Synaptics-VMM3320-MST-HUB-Firmware-Updater_DJG3X_WIN_3.12.1_A03.EXE.  I'd post a link, but most of the time that causes posts to get stuck in moderator queues.  Note that when you run the update, you have to have the system docked with an external display connected and in use, and then restart afterward.

Thanks for your suggestion. Unfortunately, my system has an i7-6820HQ CPU - according to the KB article, Intel HQ processors do not have MST hubs. The MST firmware update fix seems to apply only to systems with Intel U series processors that use such hubs. Nonetheless, I tried to install the Synaptics 3.12.1 update suggested for E5570 systems, but it failed (for obvious reasons).

How could this issue be fixed on systems with Intel HQ processors?

D'oh!  Bummer, I really thought that was going to make your day. :(  Well this is a longer shot, but have you also updated the BIOS on these systems?

Yes - BIOS has been updated to the latest version 1.17.3; this did not solve the issue.

I have the same issue with E5570's at work.  I say plural because i've switched out my laptop for another one and has the same issue.  Using 2 external screens (1 vga, 1 hdmi, both Dell monitors),  happens on or off docking station.   Switched out monitor for 1 using HDMI & one using display port, same issue.

Latest drivers (using dell command) and BIOS.   Think this must be a driver issue, because i nabbed another 5570, restored using the Windows 10 USB drive (laptops came with Windows 7 preinstalled), and don't seem to have the issue.

My two screens both run on DisplayPort. My laptop came with Windows 10 preinstalled. Updated latest drivers via Dell Command Update and Support Assist. Swapped the dock, same behavior. I was reading somewhere in the forum that a user reported to have fixed the issue after a mainboard swap...

This is interesting to me. I have the exact same behavior, but different hardware. Maybe we can help each other by ruling things out. I have a Dell XPS 13 connected to a TB16 Dock via a Thunderbolt 3/USB-C connection. I have two LG external 4k monitors running at 60 hz connected to the dock via two displayport cables (no daisy chaining). I'm running Windows 10 Pro. The computer has Intel integrated graphics (Iris 640).

My system behaves just like yours I think: one monitor or the other will periodically just turn black for a second or two. Activity on the screen makes it more likely, but it isn't application dependent. Sometimes a screen will go black several times a minute, sometimes once an hour, maybe I'll have a day where it isn't a problem. Restarting makes it worse. Powering down and turning the computer back on makes it better (usually). I've had the motherboard replaced several times, but I still have the problem. I never get an error message. All my drivers are absolutely up to date. If I connect the monitors using HDMI cables (which requires reducing the refresh rate to 30hz) the behavior goes away. If I use just one monitor, the behavior goes away. I also tried connecting one monitor directly to the laptop using a USB-C to Displayport cable (thus cutting the dock completely out) and I got the same behavior when using the external monitor with the built-in display, although the built-in display has NEVER blacked out.

I had convinced myself there was a problem with Dell's design of the USB-C port, but maybe not? It sounds like the only thing we have in common may be the DisplayPort connection.

I disabled DP 1.2 on my two U2515H monitors, and *believe* this eventually resolved the issue. Note that I was not daisy chaining the displays, but connecting them individually. So far no flickering anymore. Maybe the Dell laptops or docking stations have issues with DP 1.2...?

I just tried that and I'm still getting the disconnects. Also, now sometimes both monitors go blank at the same time, whereas before it was just one or the other.