External monitor directly via USB-C

[Hmmm]

I have a LG 27UP850-W 4K monitor that has a usb-c connection on the back. It works via alternate dp over usb-c. I can connect my macbook or my Dell laptop with no issues via the single cable but steam deck is different.
When I connect the deck, the deck charges and also I can use the mouse and keyboard connected to the monitor. But no video or audio. There isn't any information in the deck settings as well.

Does anyone have experience in making this work or is this a hardware limitation? Maybe being fixed in a later update? I have tried stable and beta thus far.

OS 3.2; Build 20220526.1

[NEET_Guerilla]

Works fine with USB-C on my Samsung M7

[ReBoot]

Are you positive this monitor supports DP input over USB-C?

[Hmmm]

Originally posted by ReBoot:

Are you positive this monitor supports DP input over USB-C?

Monitor specs list USB-C AltDP support. Also it works with my Dell laptop, that doesn't have thunderbolt. When I connect the deck to the monitor, monitor says that new input has been detected but it stays black.
I have also finished my discussion with Steam support and they said that I need to hold tight for a software update, as they are still ironing out all the bugs.

[redlum]

Same monitor, same issue. Keyboard and mouse, and power delivery working but no video. Same as op: works fine with a multitude of other devices.

Hoping a patch comes soon!

[barchanski]

I confirm that the issue still exists as of 21 September. USB hub and power delivery work, no video or signal audio though both on Steam and desktop mode (on the desktop mode no display is detected in settings)

[Hmmm]

Originally posted by barchanski:

I confirm that the issue still exists as of 21 September. USB hub and power delivery work, no video or signal audio though both on Steam and desktop mode (on the desktop mode no display is detected in settings)

Yes, still same for me as well. Doesn't look like it's their priority for now.

[Axe Raider]

Just chiming in to say that I'm having the same issue on a LG 5K Ultrafine display. Was really hoping to just use the monitor as a USB-C hub since it has so many USB-C ports on the back (and no HDMI), but the lack of USB-C video output from the Steam Deck to my monitor is thwarting all my plans.

I have a feeling they'll deploy the software update shortly before the launch of the official Valve Steam Deck dock, as that will likely be configured to work with all monitor I/O setups as a plug-and-play dock.

[sirgogo]

I can confirm this is also an issue on LG model 32QP880-B. Maybe LG-specific? I don't have another monitor to compare.

[nicechaser75]

Hello Guys,

I’ve suddenly got a similar issue, the last 3 days, which I did not have before with my Ultrawide Samsung C34J791W!

I could connect to my monitor through direct USB-C cable with no problems, and also by Jsaux Docking station (HDMI), but it suddenly started to stop to work properly:

With Jsaux:
- glitches on the Monitor and on the Steamdeck display
- The mouse cursor can only be used on the monitor
- I cannot interact with the desktop icons
- The displays are correctly set in the User Settings/Display!

With USB-C cable:
- It sometimes work not properly, duplicating the Steamdeck display on another resolution and not full screen (even if it was set)
- By rebooting, the monitor won’t be recognized anymore!

Is it possible it is a big big big mayor Issue of KDE PLASMA?


Tad

[Chakotey]

I can also agree that since a few days my external Monitor is not working.
It works always fine and with no problem but then one day to another it stopped working.

I just tested all i know, new cable, antother device (TV), factory reset (Deck) nothing helps.
But also i recognize that the vibration also stopped working :/
A little bit annoying, Steam Support give me no answer @the moment.

[chris4703]

Same here issue started just a week ago today. Worked great in my thinkvision monitor. All peripherals were recognized no issues at all. Today the deck won’t even recognize the monitor or charge from the display. Tried swapping out all cables still nothing

[jackburton09]

Hi , same here everything was working fine now ( the dock 3rd party was working no issue the mouse keyboard works and the charging ) i have 3 monitors noting works for external display

[golephish]

I didn't think there was any video on the USB port, thought it was power only. If I read this right you are connected the usb port from the deck to your monitor?

[aerou]

Eizo EV3895 via USB-C here and no issues. Charging,video, audio,ethernet,all works and in 4K even.

[redlum]

Originally posted by aerou:

Eizo EV3895 via USB-C here and no issues. Charging,video, audio,ethernet,all works and in 4K even.

The LG monitor owned by the OP and I does all this for seemingly every device (windows laptops, macs) except the Steamdeck, and never has. So maybe this is linux issue?