Show projects that support DP Alt mode while excluding USB4 connections.
Show projects that support DP Alt mode while excluding USB4 connections.
Hi all. I had a broken Lenovo Legion laptop that I dismantled since I knew it at least had a good 15in 144Hz display. I got a cheap 40pin edp driver that seems to work fine. I have tried a few cables now and always gotten a strange result. The display driver has a miniDP input for video, and USB-C for power. So far I have been running power off a power bank which seems to work fine, and I have been using a miniDP to USB-C cable. On devices that have a USB-C with DP Alt mode I get a video signal exactly as expected. However, if I plug it into a USB4 device I get no display signal at all. Most of the time Windows does not detect the display at all, but sometimes it will show a small phantom display but it wont let me output to it. It has also on a few occasions completely locked up the USB4 device it was connected to. Is there someway to force USB4 to use DP Alt mode? From what I see it should be set that way by default since it's part of the standard. Another strange thing is when connected to the USB4 port of my Minisforum EM680, it DOES show the POST screen and the BIOS menu just fine. Sounding more and more like some kind of driver issue maybe?
The EM680 is a partial exception. It displays the BIOS, POST screen, and initial loading screen, yet it consistently goes blank afterward. When connected via HDMI, it boots normally on that display but remains empty on the laptop screen.
A USB4 port doesn’t always include video output—it depends on the manufacturer’s design. Sometimes, especially with motherboards that also feature Thunderbolt, the video source must be added separately. Laptops often provide flexible display support through USB connections.