USB Issues on Mac M1

Just wanted to ask in the forum here, if there’s been any USB deafness showing up. I own one of these units, and even my keyboard that’s directly plugged in, can’t see a downstream USB device. This device is brand new, and isn’t showing up anywhere on the USB bus. It’s not showing up in USB Prober.

Outside of restarting (same monitor reload doesn’t work as I have 3 monitors), there’s no way to reset M1 Mac NVRAM.

Any insight appreciated. Cheers.

Hello @daBee,

Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

We have seen some issues with USB detection on M1 based Macs with some of our docking station models like the UD-ULTC4K. It’s possible you’re running into this particular issue: https://kb.plugable.com/question/825145

While there is no SMC reset for M1 Macs we’ve seen the following procedure can help:

  1. Unplug the dock from the Mac and unplug power from the dock. Please leave the dock disconnected until the final step.
  2. Fully shutdown the Mac. (On your Mac, click the “Apple” menu and select “Shut Down”)
  3. After the Mac has shutdown, wait for 60-90 seconds, then turn the Mac back on.
  4. After logging back in, wait for 30-60 seconds, then plug power in to the dock and plug the dock in to the Mac and see if the behavior has improved.

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry

Senior Engineer | Product Owner
Plugable Technologies

Yes I was going to fully shut down this weekend. But that isn’t the issue I have. Let me explain:

  • First, a USB device isn’t detected on anything, including the keyboard USB hub. Also not in my Plugable unit.

  • When I said “findable upon reboot”, I mean that the ability for the Plugable unit to read the video output is not realized. I have to unplug the Mac-source USB-C cable, then plug it back in for my 3 displays to get properly sync’d. I’ve been doing this since I bought the unit.

Thanks for the information! I’ll reply inline below:

-“First, a USB device isn’t detected on anything, including the keyboard USB hub. Also not in my Plugable unit.”
Perhaps I still do not fully understand, however, USB devices not being detected through the dock, or the dock itself not being detected as a USB device by the system would be a symptom of the issue I linked to earlier. Though, we usually don’t see USB detection issues unless the system has been rebooted or woken from sleep first.

Has the USB functionality ever worked, or so far nothing you’ve tried has gotten the USB ports to be functional?

-“When I said “findable upon reboot”, I mean that the ability for the Plugable unit to read the video output is not realized. I have to unplug the Mac-source USB-C cable, then plug it back in for my 3 displays to get properly sync’d. I’ve been doing this since I bought the unit.”
Two of the three video outputs (the 2x DP ports) are driven over USB data through the DisplayLink USB graphics chipset in the dock, so USB detection problems would be a high probability for this video behavior. Especially if the issue occurs after a reboot.

I would definitely recommend to try the full shutdown procedure when you have the chance and see if there’s any change.

Also, in case you’re not already doing so please ensure to use the USB-C to USB-C cable the dock shipped with. Sometimes we’ll see a third party C cable be used and that can cause issues as well if the cable isn’t of the same specification.

Best wishes,
Josh

Yes. It’s like it went deaf. But again, so did my keyboard hub which is not plugged into the dock. I will try the shutdown tonight.

Update: That power off worked. Wish I could reset it with a command, but apparently that’s not possible. Cheers

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