Mac mini M4 and KVM Switch - Limited Color Depth

[Palindrom]

Hello all,

so I bought myself the base Mac mini M4 and I try to get my grip on MacOS after being a Windows user for long now.

I still have my Windows PC and want to use both of the machines on my LG 32GP850 WQHD Monitor over the only DP 1.4 Port.


Reasons to use the DP port over HDMI are that only the DP delivers 180Hz @ 10bit RGB with G-Sync on Windows and same with adaptive sync on MacOs.

Trying to make this comfortable I bought a KVM 2 to 1 Switch with DP from Ugreen. The Switch is capable of transmitting 8k@60Hz. So my Monitors specs (WQHD / 180Hz/ 10 Bit RGB) are met.

Using the Switch on Windows I have no issues - Signals from PC to my monitor are at desired specs but the Mac only enables WQHD 180Hz @ 10bit YCBCR or 8bit YCBCR. I could not find a way to switch to 10 Bit RGB (except for going down to 100Hz)

Using the same cable without the KVM inbetween the Mac and the monitor enables immediately 10 bit RGB with 180Hz.

I can't find a way to fix this problem- the KVM should not be the direct problem, since it works on PC with no issues. There should be an incompatibility with the Mac though, which I hope to fix somehow. As far as I could do my research there is no possibility of having a FW update on the switch. And no possibility to configure anything on the Switch either.

Checking on all the specs via BetterDisplay btw, I could not find a way in Mac OS to see and change color depth.

I hope someone can help me. Currently I removed the KVM and connected the Mac directly over DP - when I turn on my Windows, I'll have to unplug the Mac and plug in the PC- which is not the end of the world, since my monior is mounted on a flexible monitor arm.

Thank you in advance

 

[Kenny99]

You have PC connected to KVM (port 1) and MAC connected to KVM (Port 2). Have you tried switching these connections? When you connect directly to the MAC which cable are you using, Monitor to KVM or MAC to KVM?
Also try having the PC and MAC connected to the KVM, select the MAC and then unplug the PC to KVM. Have you talked with the Ugreen?

 

[Palindrom]

Thank you for your input.

yes I tried switching the ports - no luck

I tried everything you said - even had only the Mac in the KVM without the PC being connected to the KVM. No luck.

The cable's are all capable of desired specs, the DP to Usb C cable works with 180Hz and 10bit RGB once connected directly without the KVM.

WHen the KVM is inbetween, it does not work.

Been spending my Saturday trying to create modified EDIDs with better display and AW EDID Editor and perplexity AI.

Nothing works. I will just return the KVM and even consider to return the Mac.

 

[dz5b609]

Welcome to the wondrous world of KVM switches not doing what they're supposed to be doing.

Only advice I can give is doing what you already did which is trial and error with different combo's and then trying another KVM if that didn't work. And once it works don't ever try changing something about it, because it probably will never work again.

 

[Kenny99]

I would be curious as to what Ugreen says just for the information. Good Luck.

 

[Palindrom]

Ugreen asked me some generic questions back and used “HDMI” although I bought the DisplayPort version. Can’t bother describing them what the matter is. Issue is more on Mac side from my pov. I wil return this kvm tomorrow.

 

[CJM]

The world is smaller than you think! I just came to this thread after you posted in my Mac scrolling thread.

I have exactly the same UGreen switch and ran into exactly the same problems on my M4 Mini. I have a thread over on GitHub where I talked about this with the developer of BetterDisplay. Have a read of it over here:

BetterDisplay doesn’t pick up HDR capability when connected to DisplayPort KVM · waydabber BetterDisplay · Discussion #3681

Setup is an M4 Mac mini on 15.1, connected via USB-C to displayport to a UGreen Displayport KVM switch, to an Alienware 3423DW. 175Hz, HiDPI, that all works fine, but under the capabilities info sc...

github.com

I did kinda get it working in a 'good enough' mode. However my trial of BetterDisplay Pro ran out and I haven't gotten around to buying it yet.

The thing is, do you really want to return it? I haven't found a better available option. Let me know if you do have something in mind, though.

 

[Palindrom]

The world is smaller than you think! I just came to this thread after you posted in my Mac scrolling thread.

I have exactly the same UGreen switch and ran into exactly the same problems on my M4 Mini. I have a thread over on GitHub where I talked about this with the developer of BetterDisplay. Have a read of it over here:

BetterDisplay doesn’t pick up HDR capability when connected to DisplayPort KVM · waydabber BetterDisplay · Discussion #3681

Setup is an M4 Mac mini on 15.1, connected via USB-C to displayport to a UGreen Displayport KVM switch, to an Alienware 3423DW. 175Hz, HiDPI, that all works fine, but under the capabilities info sc...

github.com

I did kinda get it working in a 'good enough' mode. However my trial of BetterDisplay Pro ran out and I haven't gotten around to buying it yet.

The thing is, do you really want to return it? I haven't found a better available option. Let me know if you do have something in mind, though.

Thank you for your reply - seems like a similar issue but not exactly the same. I tried everything you described in the linked thread and additionally created new edid from the scratch with aw edid editor

Nothing has helped. I just returned in the switch a couple of minutes ago.

Since I already have a usb switch which switches my keyboard and mouse I am okay for now. I can change the cables quite fastly when I need one of the systems to be connected via DisplayPort but for now the Mac stays at dp and my windows in hdmi- leading the windows system being locked to 144hz 8bit rgb and no g-sync