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Is there support for USB C DP alt mode via Thunderbolt?
(lemmy.world)
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do you have evdi installed? and if not, does it work when you reboot with the cable connected?
https://wiki.archlinux.org/title/DisplayLink
No I don't have that installed. Isn't DisplayLink something completely different?
Rebooting while connected sorta worked, but not really. When I logged in the laptop monitor went black and the external monitor was black with a white underscore at the top left as if a terminal was open. So that's something I guess but I could not use my computer at all in this state.
yeah displaylink is sort of a streaming feature, but evdi is a kernel module that makes the kernel aware of multiple monitors over usb (among other things), it's required for display plug-n-play over usb in my experience.
It is not required for the displayport alternate mode of usb-c.
It is an alternative with limited performance that is built on top of usb and does not require hardware support on the PC side.
good to know, i've never managed to get it working without. what's the recommended approach then?
If your monitor/docking station/adapter and the computer support the DP Alternate mode, then you should use that, it should be supported directly by the kernel. Problems may occur if the port is connected to the dedicated graphics and you use the internal graphics card. In my experience it worked perfectly so I do not know any good troubleshooting steps.
then, maybe it was added to the kernel after i first tried it and i've been working with old assumptions.
also that behavior is interesting because it means the display is detected and the computer is drawing to it but something in your environment is unstable. check the system log for previous boot to see what screwed up.