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

[Hmmm]

Originally posted by Škoda 14Tr:

OLED model has the same USB-C spec

LCD model: USB-C with DisplayPort 1.4 Alt-mode support; up to 8K @60Hz or 4K @120Hz, USB 3.2 Gen 2
OLED model: Display port over Type C; up to 8K @60Hz or 4K @120Hz, USB3 gen 2

Source: https://www.steamdeck.com/en/tech/deck

Slight difference in the wording, OLED model doesn’t mention the “Alt-mode support.” But yeah, I believe it is the same. Doesn’t hurt to try though.

[Prezidentas]

Originally posted by Hmmm:

Originally posted by Škoda 14Tr:

OLED model has the same USB-C spec

LCD model: USB-C with DisplayPort 1.4 Alt-mode support; up to 8K @60Hz or 4K @120Hz, USB 3.2 Gen 2
OLED model: Display port over Type C; up to 8K @60Hz or 4K @120Hz, USB3 gen 2

Source: https://www.steamdeck.com/en/tech/deck

Slight difference in the wording, OLED model doesn’t mention the “Alt-mode support.” But yeah, I believe it is the same. Doesn’t hurt to try though.

both support DP 1.4 and up to 4 lanes for displayport alt mode. perhaps the deck is having problems with 4 lane operation? most docks including official use 2 lanes (because you can't have USB 3 when using 4 lanes).

[Prezidentas]

Your monitor seems to use 4 lanes even though its resolutions should be doable with only 2 lanes. Perhaps a lead for investigation?

[Prezidentas]

Also, have you tried switching DP version in the monitor from 1.4 to 1.2?

[deaddoof]

Originally posted by Škoda 14Tr:

Also, have you tried switching DP version in the monitor from 1.4 to 1.2?

I wonder whether the cable itself the suspect. I heard ASUS sometimes provide defective cables.

[Prezidentas]

Originally posted by deaddoof:

Originally posted by Škoda 14Tr:

Also, have you tried switching DP version in the monitor from 1.4 to 1.2?

I wonder whether the cable itself the suspect. I heard ASUS sometimes provide defective cables.

the monitor in question is LG, plus the monitor works fine with other computers

[Hmmm]

This seems like LG specific problem now. The Deck works fine now with my Dell U2723QE and Dell U2722DE at work. Without changing any settings on the monitor or Deck, with the provided USB-C cable. Deck has the latest Stable firmware.

[deaddoof]

Originally posted by Hmmm:

This seems like LG specific problem now. The Deck works fine now with my Dell U2723QE and Dell U2722DE at work. Without changing any settings on the monitor or Deck, with the provided USB-C cable. Deck has the latest Stable firmware.

Welcome to the world of monitors and IHV. Everything damn thing is kinda broken in various ways. Why do you think the FOSS community wants to open everything even though there isn't much harm. Most FOSS guys are tired of inspecting broken stuff.

[deaddoof]

Originally posted by DestructoDisk:

Originally posted by Hmmm:

This seems like LG specific problem now. The Deck works fine now with my Dell U2723QE and Dell U2722DE at work. Without changing any settings on the monitor or Deck, with the provided USB-C cable. Deck has the latest Stable firmware.

I would still say it's a likely Valve issue, given that LG is one of the world's leading display distributers, and every other device works, even obscure weird stuff. I have tried every device I can imagine that does video over USB C on my monitor, and it all works, the Deck stands alone. It's not like these smaller device manufacturers have enough developers to be targeting some weird quirks in an LG device.

You must be new to hardware. Leading distributor means jack squat. Leading translate into LG bugs becomes injected into the display standard undocumented.

Whoever their display engineer is, has goofed on multiple occasions

Not really. Steam Dock provides MST which mean you can display both hdmi and display port on the same dock. Valve unfortunately did not realize HDMI consortium hates those use cases. If you can mirror a display, something something piracy.

[deaddoof]

Originally posted by DestructoDisk:

Nah Valve has stumbled over and over on display, it's not just one issue, it's not confined to the dock. or LG USB C monitors. They have had patch after patch after patch to fix display problems. The Deck shouldn't have released with the display problems it had, and the Dock after that shouldn't have released in its state. Tiny companies release stuff all the time that just works. Apple's walled garden devices that are super locked down to strict standards work on LG over USB C. Android and Windows devices that are extremely open and non conforming and have diverse capabilities and standards, work on the LG display over USB C. The only company releasing a device that doesn't work with it, just coincidently has had numerous difficulties with display out on their devices... I think it's not coincidence...

Actually. Many MST docks are broken too on Apple and Windows. Ask the home theater reddit about HDMI headaches.

You can easily google HDCP handshake bugs. They are everywhere.

I believe Apple doesn't support MST over displayport. Viola it just works by not giving you an option at all.

Valve is a tier one hw manufacturer who pushes the envelope. One you pass the envelope, you realize things are really broken. The problem is more likely other manufacturers fault. Valve did enter hardware to push the hw industry forward. Look how awful everything is.

Edit: Why do people blame the wrong vendor for broken hardware? No wonder why many hw companies are skiddish or try to choose the userbase. This thread is proof. You cannot make people happy by executing good things well. The real answer to tell LG to fix their crap.

https://community.spiceworks.com/topic/2475203-hp-laptops-having-issue-with-20-ft-hdmi-cables?from_forum=357

https://forums.lenovo.com/t5/ThinkPad-T400-T500-and-newer-T-series-Laptops/HDMI-Dock-Laptop-Something-s-not-working/m-p/5109884

I didn't even try. I googled HDMI MST Dock. You can find so many broken docks.

[deaddoof]

Originally posted by DestructoDisk:

Funny that you mention that. My official Valve Steam Deck Dock didn't work with several displays in my house at launch, but it worked with my MacBook and my iPad. I had tested

How old are your displays? The dock works better with 10yr old display. I presume HDCP version matter a ton.

Originally posted by DestructoDisk:

Seem's weird Valve has been praised since the Deck launched, since it releases so many updates. But in reality, most of the updates were fixing broken suff that the device never should have shipped with or adding the most basic features. They really should have been criticized for releasing super alpha hardware and software, not praised. Competitors don't have to release that many updates that fast, because generally they don't release a device in that poor of a state. What was it just like a month ago, Valve finally made external storage function properly. It's supposed to a PC, but a basic game console feature took a year and a half post launch to patch in.

The largest offending bugs are Linux bugs. Valve has been working on those. They fund many developers. I cannot blame Valve for many Linux bugs because these bugs will exist with or without Valve.

Valve specific bugs are breaking efi on dual boot setups. Reliance on XTest for their XInput API. Unable to maintain Linux runtime properly.

https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/431

Originally posted by DestructoDisk:

It's clear without bias they have dropped the ball on display, again and again. You can point to niche things here and there of other companies.. but it's not common for a company to release a device that doesn't work with plain old HDMI on an assortment of consumer TVs.

I think you have a misunderstanding here. Any digital rights management consortium have a general bias against Linux. AMD cannot release VRR on HDMI in Linux due to this bias. HDMI has been nothing but grief for something as important as display technology.

Originally posted by DestructoDisk:

Nintendo would have been crucified if the Switch released not working with many TVs.

Or TV manufacturers decided to add special workaround for the switch. The device is almost a decade old so manufacturers know about it.

https://www.reddit.com/r/NintendoSwitch/comments/90f86d/comment/e2q8w1o/?utm_source=reddit&utm_medium=web2x&context=3

https://www.reddit.com/r/bravia/comments/qt25jq/comment/hkgxyjv/?utm_source=reddit&utm_medium=web2x&context=3

https://www.youtube.com/watch?v=dzpwc33HyPg

I love the youtuber show an LG TV.

Originally posted by DestructoDisk:

The second example was a Thunderbolt firmware issue. Yeah it's Thunderbolt.. its not a traditional video signal, you need to have Thunderbolt to Thunderbolt connection and you need to have updated and proper firmware. My Apple Thunderbolt Display won't work with any HDMI or Display Port adapter in the world. It has to be a Thunderbolt to Thunderbolt connection. Other Thunderbolt displays may have other video options like HDMI or Display Port through USB C, but it doesn't have to, and that has nothing to do with the Thunderbolt video spec.. thats a completely different video standard.

I believe USB-C to HDMI requires active adapter while HDMI to Displayport can be passive....

Yep, HDMI consortium is a pain.

The cable length keep making me remind me of Apple's cable

https://www.youtube.com/watch?v=AD5aAd8Oy84

[Hmmm]

I received my OLED model and the same LG monitor works brilliantly without changing any settings with the monitors supplied usb-c cable. In game mode and desktop mode. I suppose there are some hardware changes with the OLED Deck.

[redlum]

Originally posted by Hmmm:

I received my OLED model and the same LG monitor works brilliantly without changing any settings with the monitors supplied usb-c cable. In game mode and desktop mode. I suppide there are some hardware changes with the OLED Deck.

Oh! Very interesting.

Meaning it probably is a hardware issue/limitation with the OG deck?

As someone who owns the same monitor, thanks for updating.

[I ate thy waffles.]

I've switched to Jovian-NixOS and my monitor works well now over DP with the official dock.

It seems like it's a software bug then.

If the monitor is your only downside to Steam Deck and you have no experience with Linux and NixOS, I do not recommend you to go that route.

[deaddoof]

Originally posted by DestructoDisk:

I didn’t pick up the OLED yet, but just watched a Gardiner Bryant video and he is saying Steam Deck is still having a lot of issues with video out, even on his TV. Uhg… Cmon Valve. If everyone else can do it, you can do it too. Little no name single board computers to Apple’s locked down ecosystem, it all just works with no fuss, but after years of patches, Valve is still struggling with basic functionality of its device 😞

dont necro old threads man.

Btw, here is the gamescope reset

https://steamcommunity.com/app/1675200/discussions/3/3771239049944984767/#c4300445879346263688

https://steamcommunity.com/app/1675200/discussions/2/4361246746316689014/