[Bootcamp Win10] USB-C to Displayport connected Display not working in 2017 MBP 13" TB

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[Bootcamp Win10] USB-C to Displayport connected Display not working in 2017 MBP 13" TB

I've read about this issue on several forums but haven't found a solution that works.

The situation:

I have bootcamp (Windows 10) on my MBP 13" 2017 with Touch-bar and it works great.

However, when I'm in bootcamp windows won't detect my 27" ILYAMA 4K display (PL2792UH) which is connected with a USB-C to DisplayPort cable. In normal MacOS mode, the display works perfectly.

When I restart and select the bootcamp partition, it briefly mirrors the windows update or log-in screen but then, after logging in or while logging in, it states 'no signal detected'.

The display has a USB-hub which needs a separate connected USB-cable to work. From the display this hub is connected through the USB-cable to an Apple HDMI-dongle to my MBP. This Apple dongle also connects the battery adapter to my MBP. I've got a USB-to-lightning cable, which connects my Apple keyboard to the display's USB-hub. This keyboard works, so the windows DOES recognise the display's USB-hub.

Note: the displayport>usb-c cable is NOT connected to the dongle, as it seems that my normal macos can't detect the display then either. So the display is connected directly, without a dongle, to my mac.

The MBP specs:

MacBook Pro (13-inch, 2017, Four Thunderbolt 3 Ports)
Videocard: Intel Iris Plus Graphics 650 1536 MB
Processor: 3,5 GHz Dual-Core Intel Core i7
16 GB 2133 MHz LPDDR3

What I've tried:

Usual ol' restart
Cold restart: aka turn mac/windows completely off - wait until caches clear- turn on windows immediately without first starting MacOS
Updating windows
Updating bootcamp
Updating the drivers through the device manager
Reconnecting the display: doesn't do anything when windows is logged in.

I've read about disabling some sort of power saving mode in regards to the usb-ports in the network adapters portion of the device manager, but can't anything resembling that.
When I look through the device manager, at 'Univeral Serial Bus controllers' there is one 'Unknown USB Device (Port reset failed)'. Though this is not always the case, so I'm not sure it's connected. Just now I did a cold reboot and there's no failed ports right now.

So, how do I get this external display working in bootcamp?

Posted on Jan 16, 2021 1:31 PM

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Answer 1

Best reply

Loner T

Level 9

59,471 points

Jan 17, 2021 6:10 AM in response to BlowYourMind

The two left TB ports are on one TB bus, the other two ports form the second bus. You can verify this in About This Mac -> System Report on the macOS side.

Your HDMI signal is 4K/30Hz. Your MacBook Pro (13-inch, 2017, Four Thunderbolt 3 ports) - Technical Specifications can support

Video Support

Simultaneously supports full native resolution on the built-in display at millions of colors and:

One display with 5120-by-2880 resolution at 60Hz at over a billion colors
Up to two displays with 4096-by-2304 resolution at 60Hz at millions of colors
Up to two displays with 3840-by-2160 resolution at 60Hz at over a billion colors

Thunderbolt 3 digital video output

Native DisplayPort output over USB‑C
VGA, HDMI, and Thunderbolt 2 output supported using adapters (sold separately)

Your StarTech cable seems to be fine.

Typically connections are

Left USBc (pick one of the two) -> USBc-DP to Monitor

Right USBc (pick one of the two) -> Digital AV Adapter -> [ USBc (goes to power), USB2/3 (Hub), HDMI to monitor]

You can flip these, as convenient.

Also, be aware that there are two versions of the adapter. See About the Apple USB-C Digital AV Multiport Adapter - Apple Support for reference. Check your model.

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Answer 2

Loner T

Level 9

59,471 points

Jan 17, 2021 9:01 AM in response to BlowYourMind

BlowYourMind wrote:

I've only got one external display, so with the DP-to-USBc cable I don't need the HDMI cable. I've got the Model A1621, so max 30Hz support. Good to know there's two versions!

👍

And well... putting the dongle with power+usb-hub-cable on the right side and the DP-to-USBc on the left did the trick. Thanks!

That is 😎.

Strange that MacOS DOES accept it with both plugged in at the left side (since on MacOS it worked perfectly), but Win10 bootcamp doesn't. Just out of curiosity, what is the difference?

The difference is in the drivers between macOS and Windows.

And if I used my other macbook pro (13" 2017 version as well, but no TB and only two USB-c connectors at the left side), an external display with DP-to-USBc just wouldn't be possible in bootcamp because of this? Because it counts as only one USB-bus?

Your MacBook Pro (13-inch, 2017, Two Thunderbolt 3 ports) - Technical Specifications does support

Video Support

Simultaneously supports full native resolution on the built-in display at millions of colors and:

One display with 5120-by-2880 resolution at 60Hz at over a billion colors
Up to two displays with 4096-by-2304 resolution at 60Hz at millions of colors
Up to two displays with 3840-by-2160 resolution at 60Hz at over a billion colors

Thunderbolt 3 digital video output

Native DisplayPort output over USB‑C
VGA, HDMI, DVI, and Thunderbolt 2 output supported using adapters (sold separately)

The driver should handle it properly. If you do see issues, we can try to test that specific configuration.

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Answer 3

BlowYourMind Author

Level 1

14 points

Jan 16, 2021 4:56 PM in response to Loner T

This is the one: https://www.apple.com/shop/product/MUF82AM/A/usb-c-digital-av-multiport-adapter?fnode=2b46dbb8a95b899ee4f2b5eee1b25462fccfaafdc2ef2d587b7f2575a7a5d9348844a6e493fff36a992af59a149ce959fe58375a060bd4c78c459377b58cbd8c7ea8f0557d3a97dab56a3c2b11989296705face2e78ffde5d90aca32a52e4ba771264d11ce3494cfe33d919710460cad&fs=f%3Dadapter-hdmi%26fh%3D4595%252B45b0%252B3058

Ah, that makes sense, thanks for the explanation. I figured it was something like that. But, since it is connected directly (display > displayport ---> usb-c > macbook), something else is amiss right, in regards to the bootcamp-display issue? I think it's driver related, perhaps, since it does work without any issues on MacOS but doesn't with the exact same setup in Win10 bootcamp? I'm just not sure how to solve it, since windows claims the drivers are up-to-date (and the only links I've seen are AMD drivers, which my MBP doesn't have due to lack of such a videocard?).

So the microphone/BT-headset is a known issue, good to know. I assume without a good solution as of now?

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Answer 4

Loner T

Level 9

59,471 points

Jan 16, 2021 5:47 PM in response to BlowYourMind

The 13-in models have two Thunderbolt buses. TB0 and TB1. Connect the Digital AAV adapter to one, and the USBc-to-DP to another. I have a 2018 MBP, and I can connect two Dell U2715H monitors to the USBc ports via USBc-to-DP cables and both monitors work properly in macOS Mojave and W10. There are HDCP requirements for the 4K monitors that you should verify the cables can support.

Try to connect the monitor via HDMI and test.

Also, see External monitor and Intel HD Graphic 400… - Apple Community which uses the same brand monitor as you do, but the monitor is a 1080p monitor.

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Answer 5

Loner T

Level 9

59,471 points

Jan 16, 2021 4:46 PM in response to BlowYourMind

BlowYourMind wrote:

The display has a USB-hub which needs a separate connected USB-cable to work. From the display this hub is connected through the USB-cable to an Apple HDMI-dongle to my MBP. This Apple dongle also connects the battery adapter to my MBP. I've got a USB-to-lightning cable, which connects my Apple keyboard to the display's USB-hub. This keyboard works, so the windows DOES recognise the display's USB-hub.

Can you post a link to the Apple dongle accessory from Apple website?

Note: the displayport>usb-c cable is NOT connected to the dongle, as it seems that my normal macos can't detect the display then either. So the display is connected directly, without a dongle, to my mac.

The Apple USBc-to-Digital AV adapter removes the DisplayPort signals from the USBc port, which requires a HDMI connection to the display if you need to connect to the monitor.

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Answer 6

Loner T

Level 9

59,471 points

Jan 16, 2021 4:48 PM in response to BlowYourMind

BlowYourMind wrote:

By the way, I've also got issues with my BT headphones: the bootcamped windows doesn't detect it's microphone (only the internal microphone). Is this solvable too?

There are known issues with BT Headsets which have Microphone and Headphones, both.

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Answer 7

BlowYourMind Author

Level 1

14 points

Jan 17, 2021 4:59 AM in response to Loner T

Mine has four (at least, it has four similar usb-c ports). The Digital AAV adapter and USBc-to-DP aren't connected to each other, they already are in separate buses.

I've tried the HDMI cable, that seems to work. (so for clarity sake: Macbook > HDMI dongle > HDMI cable > display) Is it still a driver issue, but one connected to the DP/4K? iirc, HDMI wasn't able to pass through the 4K signal when I was looking for the correct setup with my MacOS, so I needed a DP cable. With the HDMI cable, the resolution on Win10 bootcamp is 3840x2160 with 29Hz, 8bit depth. Don't know if that tells you anything :)

The cable I have is this one: StarTech.com USB-C to DisplayPort adapter cable 1m 4K / 60 Hz (CDP2DPMM1MB). The description notes something about 'DP alt mode', that the adapter works with devices that have that. It states it's compatible with Thunderbolt™ 3 ports. Edit: found this info. Black 3.3'/1m USB-C DP Alt Mode to DisplayPort 1.2 (21.6Gbps) Cable supports 4K 60Hz UHD (3840x2160), HBR2, 5.1ch Audio, HDCP 2.2/1.4 | 1080p & Thunderbolt 3 Compatible

We're one step closer since it does seem to work with the HDMI cable, but if possible I'd rather have it working with the DP cable since that prevents the need of switching around my setup whenever I switch OS'es.

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Answer 8

BlowYourMind Author

Level 1

14 points

Jan 17, 2021 8:03 AM in response to Loner T

I've only got one external display, so with the DP-to-USBc cable I don't need the HDMI cable. I've got the Model A1621, so max 30Hz support. Good to know there's two versions!

And well... putting the dongle with power+usb-hub-cable on the right side and the DP-to-USBc on the left did the trick. Thanks!

Strange that MacOS DOES accept it with both plugged in at the left side (since on MacOS it worked perfectly), but Win10 bootcamp doesn't. Just out of curiosity, what is the difference? And if I used my other macbook pro (13" 2017 version as well, but no TB and only two USB-c connectors at the left side), an external display with DP-to-USBc just wouldn't be possible in bootcamp because of this? Because it counts as only one USB-bus?

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Answer 9

BlowYourMind Author

Level 1

14 points

Jan 17, 2021 9:05 AM in response to Loner T

Thanks for the information! And the solve of course👍🏻 Do you have any resources as to how to get the newest (windows) drivers which I'd need? Then I can test if that does anything when both dongle and DP-to-USBc cable are plugged in on the left side.

The comment about my other macbook was just out of curiosity, but it's not bootcamped (and I don't need it so) so I can't test it.

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Answer 10

Loner T

Level 9

59,471 points

Jan 17, 2021 10:12 AM in response to BlowYourMind

Take a look at How to use Apple Software Update for Windows - Apple Support for Bootcamp driver updates.

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Answer 11

BlowYourMind Author

Level 1

14 points

Jan 16, 2021 2:25 PM in response to BlowYourMind

By the way, I've also got issues with my BT headphones: the bootcamped windows doesn't detect it's microphone (only the internal microphone). Is this solvable too?

Reply

[Bootcamp Win10] USB-C to Displayport connected Display not working in 2017 MBP 13" TB

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