Display over USB-C Inspiron not working

Question

I bought an Inspiron 13-7378 a few years ago. One reason I bought it has the ability to use the USB-C to display port and charge. Three years later I finally needed to use this. I bought an HP Z27 monitor. I connected the display to the laptop using the monitor equipped USB-C 3.1 cable. The display worked and the laptop was charging! This lasted about 5 minutes. Now the USB-C does not work. Most of the time the laptop does not recognize anything plugged in to the USB-C. It seems if I repower the laptop and plug it in that it realizes there is a display but it doesn't work and I get the windows limited display notification where its solution is to make sure the laptop and monitor can support USB-C Alt mode, which they both do.

Any suggestions?

Thank you

Cly28 · Answer

Do not have another cable handy. Not sue why a brand new cable that came with the monitor would not work. Meanwhile a 5 year old HDMI cable I pulled out of my drawer does work.  I even tried plugging my cell phone in to the USB C port and nothing works from there either.  But if I plug my cell phone in to the USB 2.0 it works fine.

jphughan · Answer

@Cly28  Have you tried replacing the cable?  A week ago I noticed that devices connected to my USB 3.0 hub were behaving oddly.  Then I noticed it was only the USB 3.0 devices, while the USB 2.0 devices plugged into it were fine.  I figured the hub was bad, but when I pulled up on the USB 3.0 cable intending to disconnect it, I heard a bunch of 'device connected' sounds -- and when I lowered the cable, I heard a bunch of 'device disconnected' sounds.  Somehow the USB 3.0 cable between the hub and my laptop, which I hadn't touched in probably months and had probably only touched a few times in the years I've had it, had gone bad -- and in such a way that only affected USB 3.0 devices, since USB 3 and USB 2 flow over separate pins.

jphughan · Answer

@Cly28 I've worked in IT for 15 years, so I've seen more than my fair share of equipment that was DOA. The fact that an item is brand new does not guarantee that it will work properly.

It's not clear from your post whether you plugged your cell phone into the USB-C port on your laptop or the USB-C input on the display (some USB-C phones even support video output to external displays, so the latter isn't a crazy suggestion), but if you're still using the same cable, then I would still recommend that you try another one. Otherwise, assuming you plugged your cell phone into the laptop's USB-C port, the alternative would be that there's a hardware problem with your laptop that would require a motherboard replacement, and that would be quite a bit more of an ordeal than trying a replacement cable.

In terms of a replacement, you'd need a USB-C cable that supports DisplayPort Alt Mode, USB Power Delivery up to 100W (since the display supports up to 65W, and the next step down on cable support is 60W), and at least USB 3.1 Gen 1. Not all USB-C cables support all of those things.

Cly28 · Answer

Thanks for the reply. What I meant is that I plugged my phone into the laptop using the cable to see if it's the laptop.

at your suggestion I brought a brand new USBC 3.1 cable. I use that to connect the laptop to the monitor and it still does not work. The cable does work to transfer data between my cell phone and my laptop however. So I can definitely say it's not the cable it definitely seems to be the laptop. I've never used this USB-C port and the fact that it does not work for video after the first 5 minutes means this thing is a piece of .

Cly28 · Answer

Ha. I did not realize that C R A P is a profanity.  So has anyone ever gotten display over USB-C to work on one of these laptops?

jphughan · Answer

@Cly28 Sorry to hear this. The specs definitely indicate that video over USB-C should work, and it sounds like it DID work at least briefly. Any chance that your system installed any sort of driver or firmware updates in the background that might have broken anything? I helped a user here recently who found they could no longer use their display at its native resolution, and the underlying cause was that Intel had released a buggy driver and it had been automatically pushed to their system.

Apart from that, given that you've already tried another cable, the more unfortunate possibility would be that something simply broke on either the display side or the system side. If your smartphone's USB-C port supports video output, try connecting it to the display using that USB-C cable just to make sure the display's USB-C input is still working for video as expected. If so, then it's possible something broke at a hardware level on your system.

Cly28 · Answer

my phone does support video over USB-C and that did work. Kind of cool. So I guess my next step is to uninstall some drivers on the laptop.

Inspiron

Display over USB-C Inspiron not working

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