No video on Alienware QD-OLED monitor since November update, EDID conformity failure

[ameturpoet]

Your system information

• Steam client version:
• SteamOS version: 3.5.17
• Opted into Steam client beta?: Not currently, but have tried it for testing purposes
• Opted into SteamOS beta?: Not currently, but have tried it for testing purposes
• Have you checked for updates in Settings > System?: Yes

Please describe your issue in as much detail as possible:

Video output to my AW3821DW monitor broke completely after the Steam Deck November 2023 update and hasn't worked since. I've tried 4 docks and multiple HDMI and DP cables (All of which work with the monitor with my MacBook Pro), active video converters to mask EDID, HDMI-CEC stripping adapters, HDMI scalers, deleting the modes.cfg file, updating the Deck to the preview firmware, and updating my monitor firmware, monitor safe mode, even getting a brand new OLED Deck to replace my LCD Deck, but nothing works. When booting while connected to the monitor, the Deck logo appears, but then disappears and the monitor gets no signal. When connected in Desktop Mode, the settings app seems to correctly detect the monitor and its properties, but nothing can make it display anything. I've filed a bug report with Valve and even contacted customer support, but nothing ever came of either. I'm fairly confident that this is a bug with SteamOS at this point, and others have reported this issue, too.

Here is the EDID file for the monitor which I managed to extract when in Desktop Mode: EDID

Here are the outputs for both the /sys command and xrandr while the external monitor is connected: Log File

Steps for reproducing this issue:

1. Connect Steam Deck to Alienware AW3821DW monitor with any USB-C dock and video cable
2. See that video out only appears during the boot logo, and has no signal otherwise

EDIT: Okay, I borrowed a few of my friend's USB-C docks, and I found exactly one scenario in which I was able to get video out: With the nameless USB-C dock that came bundled with PinePhone devices, I will get video out at a maximum of 2560x1080 as long as the power cable is not plugged in. This isn't ideal since it is not the monitor's correct aspect ratio or resolution or refresh rate, and the Deck cannot charge without the signal dropping.

[sebastiencaty]

I have the same issue with AW3423DW. Used to work fine with the dock but there is no output anymore since SteamOS 3.5 update (and dock firmware update). I can still get it to work with another USB-C hub (Anker powerexpand 8-in-1). Works with USB PD, full resolution and HDR.