How to build your own iMac Pro [Successful Build/Extended Guide]

[kgp]

Glad I saw this before I bought one. It's baffling. I don't recall there being these problems with Thunderbolt 2. Dang. Anyway, has anyone else here run the "Instruments" app while hotplugging to record what bad thing happened where. I did and I'd like to share it, but IDK if uploading a file that's in another forum counts as a double post. I found some interesting addresses and messages that were recorded with the app. LMK if you want to see the labeled screen capture.

BTW .. I guess you can share your findings also here in this forum or just provide a link to your respective post in the other forum.

 

[RuleBreaker01]

Here are the SwitchResX EDID dumps:

1.) DP1.4 port Titan Ridge
2.) TB3 Port Titan Ridge

you get full resolution via the TB3 using custom edid?

 

[kgp]

you get full resolution via the TB3 using custom edid?

For instance? And how to create a common edit for the two monitors implemented by macos?

 

[RuleBreaker01]

For instance? And how to create a common edit for the two monitors implemented by macos?

It was a question. I wonder if your edid changes allowed you to use the screen at full 5k2k and be working perfectly over thunderbolt, or if it was still seen as two screens.

 

[kgp]

It was a question. I wonder if your edid changes allowed you to use the screen at full 5k2k and be working perfectly over thunderbolt, or if it was still seen as two screens.

For instance was also a question ..
Can you provide a proposal for a custom edid that could work with the 5k2k? @flymovies could you dump an edid with switchresx that works with your macbook pro 15 (2018) and the 5k2k via TB?

 

[kgp]

It was a question. I wonder if your edid changes allowed you to use the screen at full 5k2k and be working perfectly over thunderbolt, or if it was still seen as two screens.

Works now with custom EDID with the LG 38UC99 connected via DP1.4 of the GC Titan Ridge and the LG 5K2K connected via TB3 of the GC Titan Ridge

If I connect the LG 5K2K alone with this custom EDID for the LG 5K2K, macOS permanently switches between 1 and 2 monitors recognised, with screen of/on in between...

LG 5K2K DisplayPort setting is on DP1.4.

 

[joevt]

I do not have a USB-C to DP1.4 converter and the latter approach would not help me at all. There is only 1x DP1.4 connector on the monitor and I have 2 PCs with a Vega each. I can just connect one PC via DP1.4 and to do so, I simply use one of the Vega DP1.4 ports which perfectly works with the appropriate 5K resolution. If there would be a second DP1.4 port on the Monitor, I could also connect the second PC simply via the DP1.4 port of its Vega. A USB-C to DP1.4 converters is basically useless in this context and just provides another DP1.4 connectivity that I can't sue because of the single DP1.4 port implementation of the LG 5K2K.

BTW... Also the DP1.4 port of the GC-Titan Ridge works flawless with the LG 5K2K.

According to the manual for the 34WK95U-W, the Thunderbolt 3 port can be used as a USB-C input. This is a feature of displays that use the Titan Ridge Thunderbolt 3 controller. The USB-C port can be used with either a Thunderbolt 3 connection (e.g. MacBook Pro) or a USB-C with DisplayPort alt mode connection (e.g. MacBook). The manual is unclear whether this USB-C connection supports DisplayPort 1.4 (it says the max resolution for USB-C is 5120 x 2160 @ 60 Hz) or only DisplayPort 1.2 (it says the recommended resolution is 3440 x 1440 60 Hz).

The Moshi USB-C to DisplayPort cable is not a converter - The DisplayPort alt mode of USB-C directly uses the 4 pairs of wires of the USB-C cable as DisplayPort lanes. The cable is bidirectional so that it can be used as DisplayPort to USB-C. This could be used to connect the second PC via the DP1.4 port of its Vega.

Alternate Mode is enabled via a USB PD protocol handshake through structured vendor-defined messages (VDM) to discover, configure, and to enter or exit Alt Modes. I think bidirectional cables do this differently than cables that are not bidirectional.

Here are the SwitchResX EDID dumps:
1.) DP1.4 port Titan Ridge
2.) TB3 Port Titan Ridge

Thanks for those. TB3 has two DisplayPort connections to your display, so there should be two EDIDs for TB3. Can you post both of them?

I can't seem to find a utility that can parse the hex EDID data better than SwitchResX can but SwitchResX is not parsing everything. I think the utilities I have are complaining about the Display ID extension blocks for some unstated reason.

I am unclear about the relationship between EDID and DisplayID. Is DisplayID a separate set of data, different than EDID and its extension blocks? DisplayID may have information about the tiling orientation of the two displays.

Works now with custom EDID with the LG 38UC99 connected via DP1.4 of the GC Titan Ridge and the LG 5K2K connected via TB3 of the GC Titan Ridge

If I connect the LG 5K2K alone with this custom EDID for the LG 5K2K, macOS permanently switches between 1 and 2 monitors recognised, with screen of/on in between...

What custom EDID? Did I miss a post? Or do you mean the custom resolution from your screenshot? Custom resolutions are separate from custom EDID. Both are stored in the files at /System/Library/Displays/Contents/Resources/Overrides
You can see how the changes you make in SwitchResX are stored by looking at those files.

 

[joevt]

Actually, the "VESA Enhanced Display Data Channel (EDDC) Standard" explains how EDID and/or DisplayID are read from a display. If only there was a good utility to parse the data.

 

[kgp]

Actually, the "VESA Enhanced Display Data Channel (EDDC) Standard" explains how EDID and/or DisplayID are read from a display. If only there was a good utility to parse the data.

Apparently, when connected together with the LG 38UC99, the Display ID of the LG 5K2K is 1.1 and there is only one 5K2K monitor implemented by OSX. If connected alone, the Display ID of the LG 5K2K seems 1.2 and OSX implements 2 monitors or premanently switches between a 1 and 2 monitor imolementation. No idea how to hardwire Display ID 1.1

Else it seems important to disable postiv sync. for the LG 5K2K connected via TB3.

 

[joevt]

Apparently, when connected together with the LG 38UC99, the Display ID of the LG 5K2K is 1.1 and there is only one 5K2K monitor implemented by OSX. If connected alone, the Display ID of the LG 5K2K seems 1.2 and OSX implements 2 monitors or premanently switches between a 1 and 2 monitor imolementation. No idea how to hardwire Display ID 1.1

Else it seems important to disable postiv sync. for the LG 5K2K connected via TB3.

DisplayID is a standard. Where do you get Display ID 1.1 or 1.2 from? Are you referring to the EXTENSION EDID BLOCK -> DID-EXT: Display ID Extension -> DisplayID version?

The manual for the LG 5K2K has a list of resolutions. It says 5120 x 2160 60 Hz has positive horizontal sync and negative vertical sync. Are you saying that doesn't work and both should be negative?

Also, my post #11535 is awaiting moderator approval (I don't know why), so watch for that.