HP lapdock as a external monitor + keyboard/trackpad through an eGPU
PREAMBLE - RANT
I purchased an HP Elite x3 Lap Dock a couple weeks ago to pair with my GPD Win Max. This was mostly because it dawned on me with usb 4.0 out (but not in any gear I've seen save the GPD Win 3), the future of lapdocks is now. I say this, knowing that I also thought this when I bought my motorola lapdock a decade ago. This time though, history will surely agree with me. With ARM becoming the latest push from apple, the crowds will likely buy in, whereas microsoft could only cater such an idea to big businesses. Novelty rarely goes far in the corporate world, but I think Apple will likely do well enough since they focus so much on supporting their hardware, vs microsoft's approach of "let's see what people do with it". In any event, phones could very well start brandishing cpu power and architecture that would upscale natively into full OSs. A phone could be a laptop for ease of sending emails, or go home and become a reasonable desktop with eGPU solution. This function also carries over to PCs. Your laptop companies now have no excuse not to make their devices scale up into powerful desktops using eGPU solutions, and niche markets like GPD/handhelds using a Switch-like format could make their win 3 be a portable gaming rig, full functioning and comfortable laptop, or powerful gaming desktop with just one cable on a device that won't become obsolete arguably in the next couple decades. You might just not have the latest resolution that newer devices are trying to standardize.
In any event, I now have a lapdock that I would like to try and use in lieu of my current monitor as the setup is way too bulky for this tiny desk. The best solution would be to run it from the eGPU to the lapdock on a stand, and hypothetically, running a thunderbolt dock between the egpu and the PC, then running usb out to be spliced back into the usb c line into the lapdock. The video out would be DP to usb c, which as I read from https://egpu.io/forums/gpu-monitor-peripherals/does-a-usb-c-monitor-support-displayport-input-over-a-usb-c-to-displayport-cable/ is probably not going to work, but this is already a very weird device, and I've been dumbfounded at just how flexible it is. I'd be willing to put the money into testing it, even if i never go further in trying to get the keyboard functioning.
PREAMBLE - RANT /END
The actual question here is "does anyone know if you can run a thunderbolt dock in line of an eGPU, or do you have to go directly from PC to eGPU? If not, is this something usb4/TB4 could fix? If it does fix this, would it also be possible for your GPU solution to run usb4 protocol out the back, which in turn carries the video/audio + whatever other inputs were in the line that it couldn't use?
Bit of an update on this thought,
I purchased an MSi Aegis desktop off of newegg because I couldn't find a reasonable price on a RTX graphics card with a USB C port on the back (only found out that was a thing after a couple days of idly looking around online for anyone attempting similar...guess virtual reality headsets use usb-c to operate) to try hooking my lapdock to. Well, turns out the listing was misleading. They claimed the device came with an nvidia rtx 2080, but what arrived was an MSi rtx 2080 super oc ventus, or similar. The key difference here, is that the MSi offering does NOT feature a usb c port, but the listing also claimed it was virtual reality ready, which it wouldn't be without that port. In any event, I'm almost positive the lapdock through epgu usb-c setup *would* work had the GPU had the port. I just felt confident with the current prices on the market for GPUs, that I'd be able to sell my old GPU and the PC and get my money back. Didn't realize how much ebay takes from a listing's final price, and now i understand why scalpers are marking their items up so much. 14.35% is an exceptionally high cut, so I'm just returning the tower back to newegg.
Maybe I'll come back to this idea later once prices settle down, if they ever do.