I’ve bought two CAC-1557 USB-C to Displayport cables to connect an M2 Mac Mini to two Samsung LF22T monitors. The monitors are new, nothing special (1080p 75Hz) and support DP1.2.
Plugging and unplugging can sometimes send a signal, most of the time they are detected but no signal. When they do send, they drop on reboot. Both monitors are set to DP 1.2.
The Mac is obviously not consistently handshaking.
Is there any firmware to deal with this or do I return them?
It’s just a cable – no complicated chips inside to apply a firmware to.
The problem is either the Mac, cable, or display. I would guess the Mac. In that case, getting replacement cables won’t help unless maybe they are a different brand or length or construction.
To test them, you need a different Mac, cable, or display to try different combinations.
One solution might be to connect the displays to a Thunderbolt 4/5 hub instead of the Mac.
Another solution might be to use a Thunderbolt to Dual DisplayPort Adapter. Then you can use the normal DisplayPort cables that came with the displays, and it would only take one Thunderbolt port from the Mac.
Thank you for your reply @joevt. I understood that this is an active cable and therefore will have circuitry and firmware in the display port connector, which is of a substantial size. Please correct me if I’ve misunderstood.
I should’ve mentioned in my original post that I have tested using a variety of Macs with different chipsets and the results are the same.
Thanks for your suggestions of solutions. I do have a Sonnet Displaylink Triple display hub which would sort the problem, but I’ve found the performance of the hub is inferior to dedicated ports for video editing and this has been confirmed by Sonnet’s support.
For now I’ve gone back to Apple HDMI adapters and straight HDMI cables. Someone I know needs their HDMI converter back though and they’re twice the price of even these cables 🙂
From searching it seems like Mac Mini TB ports are unpredictable for compatibility. If anyone has a suggestion for a TB/USB to DP cable that’s solid I’d appreciate it.
I don’t think it’s active enough to require firmware that needs updating but who knows? I’ve never heard of such a thing for this type of cable though.
Search for VESA certified bidirectional USB-C to DisplayPort cables on the VESA website?
This is an example of the simplest Thunderbolt device that can do the job:
https://eshop.macsales.com/item/OWC/TB3ADP2DPT
It depends on if the Mac mini Thunderbolt port problem goes away when you switch from using USB-C DisplayPort Alt Mode to Thunderbolt Alt Mode.
The DP signal is sent through USB-C cables without any conversion as DP ALT mode, so there is no need for advanced circuitry. Also the product you might need:
https://www.club-3d.com/en/detail/2418/thunderboltt_3_to_hdmi_2.0_dual_monitor_4k60hz_m-f/
By the way. What do you mean by monitors “set” to DP1.2?
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