Display Port and HDMI

I have a DP expansion card. I am using a DP to HDMI cable to connect to a display but it’s not working. Is DP to HDMI not a thing or am I missing something ? The cable is a quality cable. As for the OS, I tried Windows 11 and Ubuntu 21.04 with the same results.

1 Like

DP to HDMI is certainly a thing

Have you verified the cable works by using it elsewhere?

Have you tried using the expansion card in a different slot? Have you tried a different expansion card to make sure the TB4 port is functioning? Have you tried alternate ports on the display?


there is chance that this cable works in other way (not DP to HDMI but HDMI to DP) as they usually will be one directional conversions, or it’s simply broken (or it’s broken port on the expansion card/display) have you tried it with other cables and with other computer/display?


Well, I know the display’s ports are working. I don’t have another device with a DP to try the cable. And I’ve tried other slots on the laptop…. The cable specifically lists DP to HDMI as working and the other way around NOT working.

If you could provide a part number or link to a listing for the cable, someone might be able to try and reproduce your issue. I’ve been thinking of getting a cable like this, anyway.

It was this cable. I got a USB C to HDMI cable and that’s been working fine.

1 Like

Thanks for providing the link.

This cable is a passive adapter, so it isn’t compatible with DisplayPort Alt Mode. On the USB-C Wikipedia article, if you scroll down to the table titled “Alternate Mode protocol support matrix …”, you’ll see that DisplayPort Alt Mode is only compatible with HDMI via an active adapter. The expansion card probably uses DisplayPort Alt Mode, and if so, that would explain why the cable doesn’t work.


@Jacob_Padgett thanks for the detailed info. USB-C is such a cluster-mess :slight_smile:

1 Like