USB-C DisplayPort Stripey grey image on LG 27UL850 from HP Pavilion x360

[hijomojo]

Hi

Please move this message to the correct forum. This forum system is broken and doesn't allow me to post in the correct area (see: same issue as https://h30434.www3.hp.com/t5/Notebook-Hardware-and-Upgrade-Questions/cant-ask-the-community-a-quest... and https://h30434.www3.hp.com/t5/Notebook-Hardware-and-Upgrade-Questions/can-t-post-to-another-forum/m-... )

Now, my actual question:

Any ideas why I might be getting a vertical-stripey grey image when using USB-C to connect a Pavilion x360 14-dw1012tu, which is supposedly USB-C DP1.4 capable, to a USB-C DP1.4 capable display?

(edit attempt number 9: it seems posting photos directly here is what breaks the forum software. Here's a link to the photos instead: https://imgur.com/a/GEilDdx )

The monitor I'm connecting is a LG 27UL850, which is brand new out of the box, and is actually a replacement after having the first one RMA'd for the same issue. Given I'm getting the same thing again, I doubt I've received a second broken screen (though of course it's not impossible). I've done some extensive testing, and have found that other devices have no issue with the monitor; their images appear properly (Xiaomi Notebook Pro 2018, another (2019) HP laptop, and a Samsung S9, all via USB-C of course).

What's more, the Pavilion x360 works fine with the previous model of the same monitor (27UK850), however I have noticed that the refresh rate is locked at 30Hz for some reason.

I've spent quite a few hours searching and testing things but haven't had any luck so far. What I've tried includes:

updating the x360's BIOS

updating the graphics driver

using the cable from the 27UK850, which is known working

various different output resolutions from Windows, including native of course.

manually setting the monitor to specifically use DP 1.4, 1.2, and 1.1

In particular, I think a good lead would be what this display glitch is indicative of...it reminds me of what you might see with an incomplete signal, e.g. from a loose or damaged cable, but I'm using the brand new cable which came with the monitor, and as I said, the other devices had no issue.

To me it seems the hardware in the Pavilion x360 is not detecting the monitor correctly and/or is not outputting a proper DP signal over the USB-C cable. Any help with this is super appreciated!

[banhien]

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@hijomojo wrote:

.... To me it seems the hardware in the Pavilion x360 is not detecting the monitor correctly and/or is not outputting a proper DP signal over the USB-C cable. Any help with this is super appreciated!

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@hijomojo 

What is your Pavilion x360 ?  Please use the following way to find out the model/product of your machine. Not all USB-C ports are the same:

               https://support.hp.com/us-en/document/c00033108

For security reason, please do NOT post its Serial number (s/n).

Regards.

[hijomojo]

Hi Banhien,

I see you closed my second post which I finally managed to get posted into the correct area of the forum, by gradually building successful edits into a proper post. Could you please move this post to the correct area so it can be found properly?

Also, I provided my model number in the first post. It's a 14-dw1012tu

I know not all USB-C ports are the same, however the port on this device is specified as compatible with DP 1.4 and USB-C Power Delivery. https://support.hp.com/au-en/document/c06986673 

I've also tested it with a USB-C to HDMI adapter to another monitor, and that worked fine.

[hijomojo]

Just in case it's also suggested I put the model number into the Product Name field in the post settings, I'd like to mention this is not allowed for me for some reason. Likewise, I cannot set the operating system to anything other than "Unknown"

[hijomojo]

Okay, an update.

It seems the issue may not be due to something HP has done with this laptop. I recently bought another device (an Intel NUC) with the same Intel 11th Gen Core i5 1135G7, an the exact same behaviour is exhibited with that device. What's more, the NUC display works fine, until Windows finishes loading and gets to the login screen, at which point it goes all grey and stripey as in the images I uploaded in the first post. To me this rounds the issue down to either LG, or Intel.

I'll leave this post open until the exact issue/solution is found.

[hijomojo · Accepted solution]

Solved!

** ANSWER **

Courtesy of u/ShavedHamM on https://www.reddit.com/r/intel/comments/nlwdqa/intel_11th_gen_i5_1135g7_usbc_displayport/

Download LG's 'OnScreen Control' software, follow the instructions within to update the monitor's firmware (it will take 20-30mins). If you're connected via USB-C, it will probably tell you to update as soon as you start the program. This absolutely fixed the issue for me.

Download OnScreen Control from LG's list of downloads for this monitor here:
https://www.lg.com/us/support/software-firmware-drivers?customerModelCode=27UL850-W&csSalesCode=27UL...

Link to answer message: https://www.reddit.com/r/intel/comments/nlwdqa/intel_11th_gen_i5_1135g7_usbc_displayport/h4k6khc/?ut...

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