Dell U2720q Display and Macbook Pro 13" 2020 USB-stops working

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Level 1

16 points

Dell U2720q Display and Macbook Pro 13" 2020 USB-stops working

I've problems with USB. The USB-hub stops working after a while. it happens multiple times a day. Most of the time i can solve the problem by turning the monitor off and on again. But in some cases all the usb-devices (mouse, ubikey, usb-nic) stops working on my macbook and i have to shutdown my macbook. This issue doesn't effect the screen quality at all.

My setup:

Dell 2720Q, firmware: M2T101
MacBook Pro 13" 2020 model, macOs Catalina 10.15.5
Devices are connected with USB-C PD cable.
USB-devices; Mouse and networkcard attached to the monitor. (USB-A). Problem exists also with an USB-c hub connected to the port on the left of the monitor.

If i connect my peripherals to an dedicated USB-C port on my MacBook instead of the USB-hub in the screen, i have no issues at all. So my conclusion is that the problems are not caused by my peripherals, but something with 'handshaking' between display and Macbook.

I've tried to reset the NVRAM and PRAM and the problem was solved for 2 days , but not for always. Dell support can't help me because they don't supports MacOs.

USB-devices

Display-monitor

Posted on Jun 3, 2020 8:30 AM

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Answer 1

Top-ranking reply

diegofromwien

Level 1

21 points

Jun 16, 2020 4:13 PM in response to klaas226

I have the same issue:

Dell P2720D
MacBook Pro (13-inch, 2020, Four Thunderbolt 3 ports), Catalina 10.15.5
The screen's USB hub is connected via a USB-C > USB-B 3.0 cable
Logitech Wireless Mouse receiver and Magic Keyboard are both connected to the screen's USB hub.

Initially I thought it was somehow OS related, or because of the USB C to USB dongle: https://discussions.apple.com/thread/251445947

Now it seems like there is a problem with USB hubs in general, because:

when I connected the screen's USB hub via the UNI 3-in-1 dongle, the dongle's USB port was "dead" as soon as the USB connection froze. I.e.: once it froze and I unplugged the screen's USB hub from the dongle, I was not able to connect ANY USB device to the dongle. The port would proivde power, but devices were not recognized by the OS.

Another user describes the same issues (see thread linked above) using a Razer Chroma USB hub attached to an LG screen.

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Answer 2

Jun 19, 2020 1:30 AM in response to klaas226

Similar problem but with a MacBook Pro 16" 8-core 2,4ghz. External screen has turned off randomly a couple of times the last weeks, not often. But why I noticed there was a problem was because when the laptop goes to sleep it won't wake up again. It is frozen and I have to turn it off by holding down the power. This problem started the day I updated to 10.15.5. Since then I'm not letting it go to sleep. Why I think this is a similar issue is because the external screen turns off completely when it happens and I have to actually put in the power chord again on the screen to start it.

It's connected with a multiadapter where I have a USB SSD drive, HDMI and a USB extension to the screen, a 34" SE790 Samsung Curved.

In the screen I have also a Razer Chroma mouse, external keyboard, a USB midi synth and two iLok USB keys.

Plexgear Multiadapter USB-C

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Answer 3

klaas226 Author

Level 1

16 points

Jun 9, 2020 10:39 AM in response to klaas226

Hi people,

Here an update after a lot of research;

Unlike Dell's technical support, Apple was helpful in listening to this issue. Unfortunately it has not been resolved yet but I am confident. Both devices came out relatively shortly, so hope that they are still some teething problems. This USB problem has no effect at all on image quality of the monitor. The charging functionality also works well.

If a USB device is connected to the ports on this monitor, these devices may fail spontaneously. It happened to me 2-4 times a day. USB devices directly connected to the Macbook can also refuse.

Very annoying if you lose your network connection because of this. The problem can be temporarily resolved by turning the monitor on again. My advice is not to use the USB connections on the monitor itself.

The strange thing about this situation; my older 12 "Macbook had no problems with this combination.

I hope that a solution will be available soon. It is workable, but it is a pity because you still have to connect multiple cables to the Macbook.

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Answer 4

klaas226 Author

Level 1

16 points

Jun 17, 2020 1:40 AM in response to diegofromwien

Thanks for your reply

I have no idea where it may be but it really seems like a specific macbook 13 "problem. I've called Apple support for many hours and uploaded a lot of logs. I've already excluded a lot of things. It seems like something with handshaking and T2 or Gen10 processors I think, but they will be busy preparing WWDC :-)

It probably has nothing to do with the monitor itself, but rather the USB hub or USB hubs in general indeed. I often read logitech in the topics, but that can also be a coincidence.

The annoying thing about this problem is that it shows very sporadically. It is not after a certain event or activity. Sometimes I have no problem all day and sometimes several times in a row.

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Answer 5

zmoney12

Level 1

4 points

Jun 17, 2020 2:13 PM in response to klaas226

Just checking in to say I have the same issue with my 2020 MBP/RazerCoreX/USB-C Hub. Looks like it is back to the old 2015 til the decide to make their stuff usable and update us. Glad to see I am not the only one with this issue.

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