Recently I found out, that with a very short USB-C cable (30cm) the PD and video-connection is woken up! oh man .. what's the issue behind .. that's so strange now. I can not use the 30 cm cable all the time :-( The original cable approx 1,80 cm is not broken, because on another PC (Windows) everything is working fine. I guess there is a configuration issue with the tolerance of signals, detecting connections. With a long cable, respectively higher resistor value by the cable, MBP M1 running on Monterey is downgrading the connection protocol from e.g. USB4.0 or USB3.1 to something less. Please, dear Apple developer or Apple tester, with this hints, try to reproduce the issue .. obviously, several other users are facing similar issues with the USB connection. Dear community, is there anybody else who can confirm my theory or reproduce the issue by themself or solve his issue by my reported work around (shorter USB-C cable)? Thanks again already in advance.

Hej Together, I have the same issue with my MBP M1 2020 connected with an external Monitor HP S340c. Power Delivery (PD) and Video-Connection not working (but Mouse and Keyboard is still supported/working). I have opened another Thread (due to lack of knowledge that you guys already discuss this issue): https://developer.apple.com/forums/thread/693255 My Solution (recently found out): Use a very short USB-C cable (e.g. 30cm)! For me, now everything is working .. but that shouldn't be a permanent solution. p.s. Try it by yourself and report if that solves the issue also on your side! Would be a helpful information. I please Apple for support and remedy. Lets support as community as much as we can. No finger pointing as everyone (Apple developer and tester) is doing their best. Report your experience unemotionally and share as many details / data as possible that are useful to recreate your case. I am very sure that with all the relevant information and recreating the case, Apple will work out a solution. Thanks already in advance

Lets use the "Like"-Button to see faster if the short cable work around is working on your side as well.

Does anybody know, which cables are supported? I mean, which standard should be at least supported by the cable (e.g. USB4.0 or is USB3.1 already enough)? Within M1, Monterey or the MacBook Pro's at all, what is the recommended length of the cable to support Power Delivery (PD) and Video-Transmission? Technical Details on Apple-Page (https://support.apple.com/kb/SP824) shows only the connection possibility, but not the compatibility: Charging and Expansion  Two Thunderbolt / USB 4 ports with support for: Charging DisplayPort Thunderbolt 3 (up to 40Gb/s) USB 4 (up to 40Gb/s) USB 3.1 Gen 2 (up to 10Gb/s) Headphone In my case, the original cable from the monitor supplier (HP) is approx. 1,80cm and it's sticker says USB3.1 .. on my MacBook Pro M1 2020 with Big Sur on it, everything running fine on my MacBook Pro M1 2020 with Monterey on it, only mouse and keyboard functioning Using the 30cm cable (delivered within Apple's Blackmagic eGPU .. Sticked with TB3 - Thunderbolt 3, unfortunately no further details of supported protocols) .. on my MacBook Pro M1 2020 with Monterey on it, everything running fine Now I have ordered an Thunderbolt 3, USB4.0, length: 1,20cm cable and will try out, when arrived.

Hej Richard .. have you tried another / shorter USB-C cable? On my side, with the original HP USB-C Cable, no PD working but using another / shorter USB-C Cable (USB 4.0, Thunderbolt3, 1.20cm length) PD and Video is working.