Is it possible to make it work with a Thunderbolt dock?

[adams-family]

I read multiple posts about ddcctl not working with USB-C or Thunderbolt docks and I can confirm that. I have returned two docking stations only because DDC commands wouldn't work and I can't live without them :(

I tried:

• Lenovo Thunderbolt 3 Dock Gen 2 (~ 350 EUR)
• iTec USB-C dock (~200 EUR)

They are high-end docking stations, everything works on them but for ddcctl.

Example:

$ ddcctl
D: CGDisplay A7B2F66B-8B97-DFC9-DF0D-************ dispID (#45863****) (1920x1080 0°) HiDPI
I: found 1 external display

$ ddcctl -d 1
D: CGDisplay A7B2F66B-8B97-DFC9-DF0D-************ dispID (#45863****) (1920x1080 0°) HiDPI
I: found 1 external display
I: polling EDID for #1 (ID 45863**** => IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/PEG0@1/IOPP/GFX0@0/ATY,Palena@3/AMDFramebufferVIB)
I: got edid.name: LG Ultra HD

$ ddcctl -d 1 -b 1
D: CGDisplay A7B2F66B-8B97-DFC9-DF0D-************ dispID (#45863****) (1920x1080 0°) HiDPI
I: found 1 external display
I: polling EDID for #1 (ID 45863**** => IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/PEG0@1/IOPP/GFX0@0/ATY,Palena@3/AMDFramebufferVIB)
I: got edid.name: LG Ultra HD
D: action: b: 1
D: setting VCP control #16 => 1
E: Failed to send DDC command!

Is there any chance that this can be debugged / worked out? (I can help with the Lenovo dock for a couple more days)

[kfix]

I don't have any docks myself and just put up with an excessive amount of dongles. So it won't be me fixing it anytime soon.

I think this is worthy of tracking as an issue, but the Discussions board is open to try to work it out as time/hardware-collections allow.

[brunbjoern]

I have successfully used it with an elgato Thunderbolt dock together with a Dell U4320Q switching between USB-C and Displayport.
Sometimes it needs a 2nd try, but never a third.

[deodoro]

I have a OWC Mecury PRO. Switching between Displayport and HDMI work every time.