Portable display causing camera disconnect
I have an Intel Apple Mac mini (2018) running macOS Big Sur (11.6.4). I will probably take the plunge to Monterey soon, but not just yet.
For a display, I have a Dell P2418HZm monitor attached via USB-C/DisplayPort cable and one of the Mac mini's USB-A ports. I am leveraging the monitor's built-in camera for SecuritySpy. The camera, which uses the USB-A connection, looks like this in System Report:
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Dell_Monitor_IR_Webcam:
Model ID: UVC Camera VendorID_3034 ProductID_22780
Unique-ID: 0x146330000bda58fc
**
This has been working just fine for my needs. The monitor is normally switched to a different video input (via its HDMI port), and I can switch between the mini and the "regular" input via the monitor's control panel (buttons on the monitor's lower front bezel).
Recently, I've noticed that when I switch video to the Mac every so often, I have found it sitting at the login screen. After logging in, I'm informed the system was restarted because of some unknown condition and offers to report to Apple.
I decided I needed another display that was always on and also connected to the Mac in mirroring mode, so that I have a more timely idea when the system dies. I decided on the ASUS MB14AC. This connects to the Mac via another USB-C port, which converts to DisplayPort internally in the display and also provides power. (So the ASUS display only uses a single connection to the computer for which it's displaying video, and that's it.) This is what the Displays section of System Report on the Mac mini looks like:
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Displays:
DELL P2418HZm:
Resolution: 1920 x 1080 (1080p FHD - Full High Definition)
UI Looks like: 1920 x 1080 @ 60.00Hz
Framebuffer Depth: 30-Bit Color (ARGB2101010)
Display Serial Number: 1C8RN02I16ZT
Main Display: Yes
Mirror: On
Mirror Status: Master Mirror
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: Yes
Connection Type: Thunderbolt/DisplayPort
ASUS MB14AC:
Resolution: 1920 x 1080 (1080p FHD - Full High Definition)
UI Looks like: 1920 x 1080 @ 60.00Hz
Framebuffer Depth: 30-Bit Color (ARGB2101010)
Display Serial Number: M8LMTF034272
Mirror: On
Mirror Status: Hardware Mirror
Online: Yes
Rotation: Supported
Automatically Adjust Brightness: Yes
Connection Type: Thunderbolt/DisplayPort
**
This almost works perfectly. I have found that when I switch the Dell monitor from it's normal input to the Mac, though, both screens flicker as the Mac attempts to sync. the mirrored config. (which I take as normal behavior) and afterwards, SecuritySpy loses connectivity with the camera. I can get the connectivity back by temporarily powering off the ASUS display and then turning it back on. When SecuritySpy loses connectivity with the camera, it reports this:
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Error from camera "Dell_Monitor_IR_Webcam", it will be closed. (Failed to obtain video frame from local device 7100,800 The operation timed out)
**
With SecuritySpy happy with the camera again, I can switch the video input on the Dell monitor back to its usual HDMI input and the ASUS continues showing the Mac's screen with SecuritySpy's camera view working just fine. It will typically continue in this manner (even across power cycling the ASUS monitor) until I again switch the video input on the Dell monitor back to the Mac. In general, it seems the issue with loss of connectivity with the camera only happens when the ASUS display is powered on when I switch the video input on the Dell monitor to the Mac. It seems especially odd because the USB-A connection that the camera leverages doesn't change when I change the video input on the monitor.
I have also just discovered that if I extend my desktop across both displays, rather than mirroring it, this problem does not occur when I switch video inputs on the Dell monitor.
I was wondering if anyone might be able to explain this behavior, and of course, offer a solution (other than the work-arounds I've already discovered).
Thanks,
Mike
Comments
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Hi Mike, I'm not sure about this to be honest, it's a pretty niche setup and is not something I have come across before. It must be something to do with the mirroring sync that is causing some kind of interruption to the camera's USB connection.
One thing you could try is to use an HDMI connection from the Mac mini to the Dell monitor (via an HDMI switch so that you can switch between your two HDMI inputs), instead of the DisplayPort connection, while keeping the USB-A cable connected for the camera. I don't know if this would fix the problem but it might be worth a try!
Another thing would be to switch to a different/separate USB webcam instead of using the monitor's built-in camera. Or, of course, an IP camera.
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Ben,
I greatly appreciate the suggestion. To troubleshoot, it was actually quite easy for me to just swap the inputs on the Dell monitor so that the mini was using the HDMI input and the "regular" connection moved to the Dell monitor's DisplayPort input. (That regular connection was previously via DisplayPort-to-HDMI cable so I swapped it with a DisplayPort-DisplayPort cable.) Switched back and forth between the inputs on the Dell monitor and no problem with the camera at all. Issue resolved!
FYI, I had already explored moving the monitor connections around on the TB ports on the mini, so this was really the next logical step. It was just a little more involved, since I had to swap and/or re-route a couple cables.
Much obliged,
Mike
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Hi Mike, glad to hear you have found a good solution! I hope everything continues to run smoothly with your new configuration.
