LG 34UM95-P Ultrawide Thunderbolt 2 display w/ M1 & PC

[imrazor]

I picked up this older TB2 Ultrawide (3440x1440) display not too long ago. While it works perfectly as an ultrawide display, it supposedly supported a few features that don't work, or at least not as expected. The monitor supposedly supports a 'side by side' mode with two of its four inputs. Theoretically you should be able to hook up two separate computers (Mac or PC) and use the ultrawide as two independent displays in one.

As best I can tell, one should be able to hook up a computer, set the display resolution at 1720x1440, and that should be it. However when I try this, instead of displaying the screen at the proper ratio it is squashed in half vertically, leaving two huge black bars on either side. The closest way I can get to the desired functionality is to set the side-by-side systems at 1280x1024, which does NOT distort the output. That's not horrible, but not what I'm looking for.

Another bit of weirdness is Thunderbolt support. With an Apple TB3->TB2 adapter, my M1 MBA has no problem hooking up to the display, and using the monitor's USB ports to boot. However, trying to hook the monitor up to a PC laptop with Thunderbolt 4 (and the Apple adapter in between) gets diddly squat. The display is not even recognized in the PC's settings.

Any ideas on how to resolve either issue?

 

[joevt]

I think PCs with Thunderbolt 4 don't support Thunderbolt 1/2 anymore? Use the DisplayPort or HDMI inputs instead.

For side by side, 1720x1440 is the best mode to use. Does the mode exist? Use SwitchResX, double click the current resolution, and verify that it says the active pixels is 1720x1440.

Do you have the onscreen control software?
https://www.lg.com/ca_en/support/product-help/CT20098114-20152996205833

Maybe it's the Mac ScreenSplit software at:
https://www.lg.com/ca_en/support/product/lg-34UM95-P.AUS

 

[imrazor]

Well, I've got some good news but mostly bad news. The bad news is that:

1) The only supported software listed on my monitor's (34UM95-P) support page is "True Color Pro" and "ScreenSwitch". The "Dual Controller" software is TCP/IP based mouse & keyboard sharing which is a bit useless for me, since the laptop I'm using can only run Linux. (More on that in a bit.)
2) The True Color and ScreenSwitch software will either not run or not function on my M1 MacBook Air.
3) I do not have admin access on my work laptop, so I can't install the Windows software, which looks to have more functionality than the MacOS software. I uninstalled Windows on my personal laptop some time ago, but I tried to reinstall Win10 to see if any of this software would work. No matter what I tried, the Windows installer couldn't find the two onboard m.2 drives, despite manually feeding it the Intel RAID/RST drivers (as instructed by Asus support docs.)

There is some good news for me though. While the LG provided software will not run properly on my M1 MBA, it will function properly on my 2012 rMBP. That said, the True Color Pro software requires a calibrator, which I do not have. The ScreenSwitch software allows for automatic window sizing and repositioning, which is nice - but I thought it would let me have direct control over the monitor. (The Onscreen Control software will not install either.)

And one final oddity is that while ScreenResX will let me create a custom resolution of 1720x1440 on the M1, it still retains gets squashed in half vertically in PBP mode. On the rMBP however (running Catalina), ScreenResX will automatically detect and display 1720x1440 perfectly, and as god intended. I'm not sure if that is because of architectural differences (Intel vs ARM), the older OS on the rMBP, or native TB2 support on the rMBP. I do seem to recall something about recent versions of MacOS using scaling for ALL resolutions, but that could just be hearsay.

Anyway, it's been an interesting adventure but I can't say I'm entirely pleased with the results. I had been hoping I could use it in split screen mode with two separate inputs, but it looks like that's just not going to work. That said, it functions perfectly (and rather well) as a single input ultra wide.