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GC-ALPINE RIDGE in hands

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Well, I'm telling you very clearly - I wrote a utility to control display properties via DDC/CI. I have an LG 5K UltraFine display.

The display reports the wrong information via DDC/CI, so while it is possible to send commands to the display, there is no guarantee of the current state of the device via DDC. The display has an internal USB device that is used by macOS to control the various properties on it's internal USB 2.1 hub "USB Controls".

Does changing brightness work via DDC/CI? Yes, it did for me. However, it wasn't reliable and while you could send through values, even the min/max values were filled with garbage data on this display.

The USB controls work fine with my X299 build under macOS, via TB3 on a GC Alpine Ridge add-in card (at least until the display is disconnected).
 
tonyarnold said:
Does changing brightness work via DDC/CI? Yes, it did for me. However, it wasn't reliable and while you could send through values, even the min/max values were filled with garbage data on this display.
Click to expand...

Thanks for that. Did DDC utilities have the same issues in Windows? Intel graphics vs AMD?
 
Sorry, no idea - I don't use Windows.
 
Has anyone successfully used the GC-ALPINE RIDGE rev 2.0 card to passthrough dual displays using both USB-C outputs? I'm trying to use two LG UltraFine 4K displays, but can only get one to work.
 
Robotronic said:
Has anyone successfully used the GC-ALPINE RIDGE rev 2.0 card to passthrough dual displays using both USB-C outputs? I'm trying to use two LG UltraFine 4K displays, but can only get one to work.
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Did you try each DisplayPort input separately to verify that they both work? Same with the DisplayPort outputs of the graphics cards.
 
joevt said:
Did you try each DisplayPort input separately to verify that they both work? Same with the DisplayPort outputs of the graphics cards.
Click to expand...

Yes.

My GPU has two DisplayPort outputs. In testing, I connected one of the outputs to the GC-ALPINE RIDGE on Mini DisplayPort input 1, which passes through to the LG UltraFine 4K on USB-C output 1. Simultaneously, I connected the other GPU DP out directly to another display with a DP in, and the two displays work normally.

Another scenario I tested is connecting both GPU DP outputs to the Mini DP inputs on the GC-AR, along with one LG UltraFine 4K connected to the GC-AR, and another display connected via HDMI to the GC-AR. Both displays work in this case, however, the GC-AR input/output routing is strange: the Mini DP input 1 gets routed to the HDMI output, and the Mini DP input 2 gets routed to USB-C output 1, not output 2.
 
The GC-ALPINE RIDGE has three outputs: HDMI 1.4, Thunderbolt 3 port 1 and Thunderbolt 3 port 2. The two DisplayPort inputs can only go to two of the outputs at most. If two displays are connected to one Thunderbolt port (via additional Thunderbolt devices), then both inputs will go to the one Thunderbolt port. The inputs are not tied to any particular output. The display routing will be set when you connect inputs or outputs.

Did you install any software with the LG UltraFine 4K displays? I would try removing that.

Did you try Windows?

Are the USB functions of the LG UltraFine 4K working?
 
joevt said:
The GC-ALPINE RIDGE has three outputs: HDMI 1.4, Thunderbolt 3 port 1 and Thunderbolt 3 port 2. The two DisplayPort inputs can only go to two of the outputs at most. If two displays are connected to one Thunderbolt port (via additional Thunderbolt devices), then both inputs will go to the one Thunderbolt port. The inputs are not tied to any particular output. The display routing will be set when you connect inputs or outputs.

Did you install any software with the LG UltraFine 4K displays? I would try removing that.

Did you try Windows?

Are the USB functions of the LG UltraFine 4K working?
Click to expand...

Yes, I know that only two outputs can be used at a time. I don't even care about using the HDMI output, I was just testing it.

I did not install any software for the LG displays.

I have not tried Windows, from what I've read they don't work very well in Windows anyway.

Yes, the USB functions (brightness control, sound output) do work on the one display that passes through correctly. I did determine that the header cable must be connected to the motherboard for this functionality, otherwise you only get display passthrough.

I went so far as to purchase a second GC-AR card, thinking the first one was bad, but the second one behaves the same. I have tested in two different motherboards, the Auros Gaming 7 and an ASUS Prime Z370-A. I also tried putting both cards in the Auros simultaneously, but that resulted in only one of the them outputting a signal to the LG 4K, though it appeared the one active monitor was considered by macOS to be the secondary display because the Dock did not appear, and it also introduced terrible lag on the mouse input.
 
Robotronic said:
Yes, I know that only two outputs can be used at a time. I don't even care about using the HDMI output, I was just testing it.

I did not install any software for the LG displays.

I have not tried Windows, from what I've read they don't work very well in Windows anyway.

Yes, the USB functions (brightness control, sound output) do work on the one display that passes through correctly. I did determine that the header cable must be connected to the motherboard for this functionality, otherwise you only get display passthrough.

I went so far as to purchase a second GC-AR card, thinking the first one was bad, but the second one behaves the same. I have tested in two different motherboards, the Auros Gaming 7 and an ASUS Prime Z370-A. I also tried putting both cards in the Auros simultaneously, but that resulted in only one of the them outputting a signal to the LG 4K, though it appeared the one active monitor was considered by macOS to be the secondary display because the Dock did not appear, and it also introduced terrible lag on the mouse input.
Click to expand...
The only thing I can think of that could be causing this problem is that the LG UltraFine 4K is slightly larger than a 4K display (3840x2160 or 4096x2160) at 4096x2304. Maybe the GC-ALPINE RIDGE has a bug in the firmware that does not allow two of them to be connected simultaneously even though they are connected to two different Thunderbolt 3 ports. That would be strange since Apple says you can connect four of them to an iMac Pro (but only at 8bpc).

Do you have a display that is 4K or smaller that can be connected to a USB-C port (with or without adapter)? Connect that display first, then the LG UltraFine 4K, then disconnect the first display and connect the second LG UltraFine 4K.
 
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