Using a Thunderbolt peripheral firmware on a Thunderbolt host controller? Your idea is to use the GC-TITAN RIDGE as a peripheral?
Exactly! My idea came form AKiTiO Node Pro. As you can see in the pictures in below, the main part of AKiTiO Node Pro is composed of two pcbs: Thunderbolt 3 AIC and PCIe Adapter.
Besides, taking a close look at Thunderbolt 3 AIC in AKiTiO Node Pro, you'll find that it's very similar to those normal Thunderbolt 3 AIC, such as GC-TITAN RIDGE and GC-ALPINE RIDGE.
I conclude that the firmware is the key point that can decide a Thunderbolt 3 AIC to be host mode or peripheral mode. Therefore, we can also change Thunderbolt 3 AIC in AKiTiO Node Pro to become host mode by flashing another firmware into it, so that it can be used on our PC !
<<Inside of AKiTiO Node Pro>>
<<Thunderbolt 3 AIC from AKiTiO Node Pro>>
<<PCIe Adapter from AKiTiO Node Pro>>
<<Comparison between Thunderbolt 3 AIC from AKiTiO Node Pro and GC-TITAN RIDGE >>
What is the GC-TITAN RIDGE connected to?
You need a PCIe x4 female to PCIe x4 female cable to connect a PCIe card such as a GPU? I would test with a cheap USB PCIe card firstly. But that can't work because you need to provide power to both the AIC and the PCIe card. Maybe you can replace the Thunderbolt controller of a Sonnet Echo Express PCIe expansion box (or similar) with the GC-TITAN RIDGE?
This is a good idea, but I do not have any eGPU box yet so that I can't do the replacement to test it. Hence, I'm now looking for a PCB which can connect AIC and Graphic Card, also provide power to each other at the same time.
The point of this would be to create an eGPU with DisplayPort inputs that can drive a Thunderbolt display - similar to a BlackMagic eGPU except that the GPU is upgradeable.
The alternative would be to create software that can enable a GC-TITAN RIDGE that is inside a Thunderbolt PCIe expansion box - this might be simpler than using the GC-TITAN RIDGE as a peripheral.
As much as I know, you can do the same thing by GC-TITAN RIDGE. GC-TITAN RIDGE has two DP 1.4 input ports, so the card can connect with the Graphics by DP port and use thunderbolt 3 port to drive a Thunderbolt display.
This is the example from GC-ALPINE RIDGE. I think GC-TITAN RIDGE can do the same thing, too.