System with hybryd graphics (AMD). Can use screen attached to HDMI (attached to dGPU) with KDE/Wayland?

[callegar]

Hi,

working on an Asus Zephyrus G14 (2022), GA402RK to be accurate. This machine has hybrid graphics, with iGPU (AMD rembrandt 680M) and dGPU (AMD navi 6800S).

Laptop panel is mux attachable to either GPU. HDMI is hardwired to dGPU.

Using wayland session.

Is Kwin up to using an external monitor attached to HDMI without forcing the system to use dGPU only? With Xorg, think this required “reverse PRIME”. Is there some similar concept with KDE/Wayland?

Not being able to use HDMI is annoying, because otherwise you need to pull graphics out of the USB-C port attached to the iGPU, which already means carrying a usb-C to HDMI adapter with you. Furthermore the USB-C port providing video with the iGPU is the only one PD capable, so you loose the ability to power the machine via USB-C unless you have a PD enabled, 100W USB-C to HDMI adapter. And PD powering is important because the original power supply weights like a desktop system (almost ).

[megavolt]

@callegar

Is Kwin up to using an external monitor attached to HDMI without forcing the system to use dGPU only? With Xorg, think this required “reverse PRIME”. Is there some similar concept with KDE/Wayland?

Usually you can easily test it by switching to wayland on the login screen (button on the bottom left I guess on SDDM).

[callegar]

Solved the mistery.

The display attached to the HDMI connector, and thus to the dGPU is not detected until you run anything with DRI_PRIME=1, so switching on the dGPU that is otherwise suspended for power saving.