Type c DisplayPort alt mode doesn't get detected automatically on boot

General system Kernel, boot, graphics & hardware
1

I recently got a new external monitor. I am on an HP victus 16-s0xxx and I am using a type C to DisplayPort adaptor to connect to the monitor as the HDMI cable kind of lags in games (dont know why).

The annoying thing is that, when I boot my laptop while the display is plugged in and on, it doesnt get detected (no signal on the display) until i manually replug the type c adaptor and put it back in.
Is there a way to fix this? Maybe a software replug ? (I have no experience in scripting or anything, im new to linux, have been using for 1 month)

Im on KDE plasma (wayland), also if it is helpful, the type c port is wired to the iGPU (amd).

Thanks in advance for any help!

2

Hey! Good to have you with us! The only way I’ve been able to work around this with my DP monitor is to make sure it’s plugged in and turned on before I turn on the PC. It’s a known issue with DP for now, so your success might be limited until it’s fixed in kscreen2.

This might be helpful : https://discuss.kde.org/t/displayport-monitor-failure-after-wake-from-sleep/7845

Edit : I’ve dug into this a little more, and deleting the kscreen config folder to reset doesn’t have any effect. Definitely an upstream bug we’ll need to wait on.

3

hey and thank you. For me the workaround is to have my monitor turned off and when i turn on the pc to then turn on the monitor, maybe its the same thing but im not really sure. Thanks either way telling me its a known issue!

4

Yeah, the core of the issue is that Displayport behaves differently when devices are powered off ; this helps to explain it a little more ; https://forums.developer.nvidia.com/t/wayland-dp-hotplug-failure-with-hdr-display-permanently-lost-rtx-4070-580-126-09/362206

5

So I just have to wait until a patch is released?

My friend with a Thinkpad and debian (still kde plasma on Wayland I think) didn’t have this issue when he tried his laptop with my monitor and the adaptor

Also what is the downside of using X11?

6

Yep, the root bug is here ; 516974 – Wayland: Display permanently lost after DP monitor power cycle on NVIDIA 580 with HDR enabled (Plasma 6)

It’s not specific to USB-C, but the way that Wayland detects the info for monitors (known as EDID) at boot. If it misses that window of detection, it doesn’t try again, so yes, we’ll all have to wait for now.

There’s no downside per se for using X11, if it works for you, use it. X11 will eventually be deprecated by most distros in the coming years, but for now, if it’s available, it’s an option for you, and it does what you need, there’s no reason not to use it.

7

Ok i tried out x11 and the issue still persists. Maybe its my laptop’s issue or it also exists on X11. I’m not really sure, thanks for telling me its a known issue at least! Cheers