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cock-o-nut

Do USB 3.0 hubs in displays work over DisplayPort?

1 hour ago, Enderman said:

no it does not

"display port" is literally a "display" port

not some generic data port

its for "display"s only

 

you need to connect a USB cable to the monitor to be able to use the USB hub

 

1 hour ago, Benergy said:

I think you are thinking of 'thunderbolt', which can simultaneously carry display data and USB data

DisplayPort specifies up to four lanes of display data but also an auxiliary data lane that can be used for anything, including USB or ethernet.

 

AFAIK the DisplayPort 1.2 aux lane only has enough bandwidth to accomodate USB 2.0, so any USB 3.0 hub would need to connect through a dedicated cable. As you've noticed though, in practice the aux lane is rarely used for anything beyond basic management commands for the display and such. Special functions like ethernet or USB would need support from the graphics card and drivers in order to route data through the GPU's outputs. So, if it were used it would most likely be found on laptops or tablets. But, there have been developments since the DisplayPort specification was designed, and with the introduction of USB Type-C with DisplayPort Alt Mode, the DisplayPort aux channel feature is effectively obsolete and I doubt it will ever see a move from the industry to implement it. Instead, we will see the opposite, DisplayPort carried through USB ports ;)

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Posted · Original PosterOP

In theory it is possible that USB 3.0 hubs in displays are connected via DisplayPort to the computer. However, I've never seen that in practice.
Has someone experience with this or can test this?

I am looking into displays like the x34 predator, but I am worried that the USB 3.0 connectivity is only via the extra USB cable and not over DisplayPort.

For me, it would be a nice setup when coming home from work: plug only 1 cable (DisplayPort) into my laptop and use the external mouse and keyboard over DisplayPort.
This would be a clean work setup, at least in theory.

Here is a sketch of what I had in mind (notice my MVP photoshop skills):

 

workspace_big copy.jpg

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I have the exact same monitor as in the picture shown (LG 34UM95) and i can atleast for this display it dose not work over dp. you have to connect a usb3 uplink cable


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no it does not

"display port" is literally a "display" port

not some generic data port

its for "display"s only

 

you need to connect a USB cable to the monitor to be able to use the USB hub


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30 minutes ago, cock-o-nut said:

In theory it is possible that USB 3.0 hubs in displays are connected via DisplayPort to the computer. However, I've never seen that in practice.
Has someone experience with this or can test this?

I am looking into displays like the x34 predator, but I am worried that the USB 3.0 connectivity is only via the extra USB cable and not over DisplayPort.

For me, it would be a nice setup when coming home from work: plug only 1 cable (DisplayPort) into my laptop and use the external mouse and keyboard over DisplayPort.
This would be a clean work setup, at least in theory.

Here is a sketch of what I had in mind (notice my MVP photoshop skills):

 

 

I think you are thinking of 'thunderbolt', which can simultaneously carry display data and USB data


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Posted · Original PosterOP
53 minutes ago, Enderman said:

no it does not

"display port" is literally a "display" port

not some generic data port

its for "display"s only

 

you need to connect a USB cable to the monitor to be able to use the USB hub

Of course it can. The feature is called USB over AUX, since the DisplayPort v1.2 Standard specifies this in its Link Layer.

 

 

You'll find information in the displayport press release:

Another new feature is the ability to support high-speed, bi-directional data transfer, allowing USB 2.0 or Ethernet data to be carried within a standard DisplayPort cable. For DisplayPort v1.2, the maximum data rate of this “AUX” channel has been increased from 1 Mbps (Mega-bit-per-second) to 720 Mbps, providing suitable bandwidth for USB 2.0. The DisplayPort cable can therefore support USB data to/from the display to support Display USB functions, in addition to sending the video and audio information. Standard Ethernet can also be transported in the DisplayPort cable.

 
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Posted · Original PosterOP
39 minutes ago, Benergy said:

I think you are thinking of 'thunderbolt', which can simultaneously carry display data and USB data

However you are right that thunderbolt definitely works, in theory displayport should to.

Another new feature is the ability to support high-speed, bi-directional data transfer, allowing USB 2.0 or Ethernet data to be carried within a standard DisplayPort cable. For DisplayPort v1.2, the maximum data rate of this “AUX” channel has been increased from 1 Mbps (Mega-bit-per-second) to 720 Mbps, providing suitable bandwidth for USB 2.0. The DisplayPort cable can therefore support USB data to/from the display to support Display USB functions, in addition to sending the video and audio information. Standard Ethernet can also be transported in the DisplayPort cable.

 
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Posted · Best Answer
1 hour ago, Enderman said:

no it does not

"display port" is literally a "display" port

not some generic data port

its for "display"s only

 

you need to connect a USB cable to the monitor to be able to use the USB hub

 

1 hour ago, Benergy said:

I think you are thinking of 'thunderbolt', which can simultaneously carry display data and USB data

DisplayPort specifies up to four lanes of display data but also an auxiliary data lane that can be used for anything, including USB or ethernet.

 

AFAIK the DisplayPort 1.2 aux lane only has enough bandwidth to accomodate USB 2.0, so any USB 3.0 hub would need to connect through a dedicated cable. As you've noticed though, in practice the aux lane is rarely used for anything beyond basic management commands for the display and such. Special functions like ethernet or USB would need support from the graphics card and drivers in order to route data through the GPU's outputs. So, if it were used it would most likely be found on laptops or tablets. But, there have been developments since the DisplayPort specification was designed, and with the introduction of USB Type-C with DisplayPort Alt Mode, the DisplayPort aux channel feature is effectively obsolete and I doubt it will ever see a move from the industry to implement it. Instead, we will see the opposite, DisplayPort carried through USB ports ;)

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