Oh my.. thanks for the prompt about this. I just dialled out from my phone today and as soon as I hit dial the DP display went black! I think you're onto something here
Easy fix: reduce Output Power of your WIFI, found in advanced properties of the WIFI, to 75% or 50% in some instances or swap the WIFI card for Intel card.
Same with me. All drivers up to date but usbc is the only way to get a decent external monitor working to a. DisplayPort. When I use a simple HDMI only cable, I'm getting a proper signal to an external dell monitor (34 inch) which does not turn off, but only at 50mhz which makes my eyes hurt after a while on such a large monitor. I tried 3 different usbc to DisplayPort dongles and all work, BUT for a few minutes if that, before the external screen turns blank for a few seconds and it keeps repeating itself no matter what I do. I have also noticed the problem is more pronounced if my power cable is not plugged into the laptop leading me to think it's all related to power issues of some sort when using the usbc. If indeed it's because wifi is taking all the power off this laptop or conflicting with usbc. Unfortunately if my wifi is turned to half its not strong enough to work on as I have a weak wifi signal as it is so I guess I will have to buy another wifi card and tinker with the machine. So I would like to try the solution mentioned here and elsewhere to change the wifi card (as long as it doesn't ruin the warranty) then can you kindly point a link to the compatible wifi card I can swap it too that seems to work?
I have a Dell 34 inch monitor that I cannot get to work at all with a CableCreation USB-C to Displayport adapter. The Amazon add that I purchased it off had many reviews where this was 'plug and play' easy with the a Dell XPS 9550. What am I missing? Tried with and without power adapter and reducing the wifi power as stated above.
I've had the notebook a week and I'm about to send it back as I need a good docking solution.
Two days ago my dell "supportassist" software came up with message for driver updates - video, chipset and thermal with video being critical (for Intel Graphics 540). Installed those on my 9350 and now the external screen (4K @60Hz though T3-Display port Startech dongle) works rock solid... Fingers crossed, almost two days of heavy use + internet, no video signal drops...
Don't mean to be funny but did it plug all the way and click? It took me a day to realise the usbc needs a click at the end u like regular usb.
The 9350 and 9550 are diffegrent beasts. Both with usbc, but as they are different machines not nessacrily a fix for the 9550 I'm afraid.
Tried reducing the wifi even Down to 25% in preferences of the wifi card, didn't work I'm afraid, still dropped my usbc to DisplayPort signal on the 9550 I'm afraid, just not as often, but still enough to be impossible to work with...
I updated all the drivers and bios to 1.4.4 on a new XPS13 after failing to get the Dell WD15 docking station to work with resulting HDMI screen flickering and USB 3.0 devices intermittently failling (on the docking station).
I started to suspect USB-C problems as the USB 3.0 on the host computer worked well and HDMI and USB 3.0 were iratic on the docking stations.
I personally tested FOUR brands of USB-C docking stations/slash adapters, the first being Dell, and they all exhibited the same behavior of interemittent operation.
I called dell...the Dell tech reverted the Windows10 instance to its factory default and worked for four hours to no avail. They missed the follow up support call.
I'm a software delvelopment guy so I knew what I was looking at. The Windows device manager for the Plugable DisplayLink display device can be seen loading and unloading, seemingly happy then failing. DisplayLink is included in Windows10 now. This behavior mimics the syptoms of the display flickering and USB 3.0 faillures. The Plugable DisplayLink was replaced with one that had worked with an XPS13 they had and it still failed similarly. The models I tried were:
Dell WDF15 shipped from Dell with the new XPS13
StartTech USB-C Dual Monitor (MST30C2DPPD)
Pluggable USB-C Triple display (DisplayLink Driver included with Windows 10)
Pluggable USB-C Triple display #2 (bench tested successfully by Plugable on an XPS13)
Mokin USB-C to HDMI/USB 3.0 adapter
My research of the literature on the Internet suggests some models having problems with associated wifi cards (either adjusting the power to 75% which did not work for me or completely replacing the card with an alternative brand). My guess would be that there could be a particular subcomponent (like wifi or usb) that interfers with the USB-C components and causing the driver to fail. If Dell did the research on support cases they may find the correlation but that requires something to think about it. I'm waiting to see what Dell does.