What happens in a Titan Ridge laptop - Alpine Ridge dock - DP 1.3 monitor scenar...
 
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What happens in a Titan Ridge laptop - Alpine Ridge dock - DP 1.3 monitor scenario?  

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chx
 chx
(@chx)
Estimable Member
Joined: 3 years ago
 

I wrote this up at https://superuser.com/q/1534726/41259 

Given:

  1. A laptop with a DP 1.4 capable GPU and Titan Ridge
  2. A dock with Alpine Ridge with a DisplayPort and downstream TB3
  3. A monitor requiring DP 1.3 (say 3440x1440 @ 144 Hz )

What happens if the monitor is plugged into the DisplayPort and what happens if plugged into the downstream TB3?

Lenovo ThinkPad 25 -- GALAX SNPR TB3 1060 -- Lenovo Graphics Dock -- Benq BL2411PT - - two PackedPixels - Dasung not-eReader backer


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joevt
(@joevt)
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Joined: 3 years ago
 

@chx, The Alpine Ridge can only output HBR2. Therefore, if the display is connected to the Alpine Ridge (either through DisplayPort or downstream Thunderbolt port), then the laptop will have an HBR2 connection to the display.

You need to connect the display to a Thunderbolt device with a Titan Ridge controller to get an HBR3 connection. You can connect it after the Alpine Ridge device. The Alpine Ridge device will pass the Thunderbolt DisplayPort 1.4 stream unmolested (since it is Thunderbolt) to the Titan Ridge device which will convert the stream to HBR3.

https://www.amazon.ca/Wavlink-Thunderbolt-DisplayPort-Resolution-Compatible/dp/B07S8W49T1

 

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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chx
 chx
(@chx)
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Joined: 3 years ago
 
Posted by: @joevt

he Alpine Ridge device will pass the Thunderbolt DisplayPort 1.4 stream unmolested

What if you connect via USB C DisplayPort Alternate mode? Does that break it? I just do not have a clear metal image of what exactly the Alpine Ridge does to the DisplayPort packets :/

Lenovo ThinkPad 25 -- GALAX SNPR TB3 1060 -- Lenovo Graphics Dock -- Benq BL2411PT - - two PackedPixels - Dasung not-eReader backer


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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

A Thunderbolt DisplayPort stream created by a DisplayPort input adapter in a Thunderbolt host controller is sent to a DisplayPort output adapter in a Thunderbolt peripheral device controller.

It is only sent to one DisplayPort output adapter. It would be interesting if it could be sent to multiple output adapters - maybe it could be, if the pairing of input adapters to output adapters wasn't automatic.

Let's say a DisplayPort output adapter of Alpine Ridge is paired with the DisplayPort input adapter of Titan Ridge which happens when you connect a display to the Alpine Ridge (via a DisplayPort output or a USB-C with DisplayPort alt mode output connected to the DisplayPort output of Alpine Ridge, or to the downstream Thunderbolt port of Alpine Ridge). Since the Alpine Ridge has lower capabilities (HBR2) than Titan Ridge (HBR3) then the DisplayPort connection is HBR2. The GPU sends a HBR2 signal to the Titan Ridge, then the Titan Ridge converts it to Thunderbolt DisplayPort packets, and finally, the Alpine Ridge converts it to DisplayPort.

If the display is connected to a Titan Ridge after the Alpine Ridge, then the Alpine Ridge does nothing to the Thunderbolt DisplayPort packets. The peripheral Titan Ridge has the DisplayPort output adapter that is paired to the DisplayPort input adapter of the host Titan Ridge. Both have HBR3 capability, and the display is HBR3, so the connection will be HBR3.

You can use the AGDCDiagnose command in macOS to view DisplayPort connections and registers.

You can use the ioreg command to see Thunderbolt controller DisplayPort input and output adapters.

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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