Gigabyte M28U & Mini M1 - how to get 4K (1080 retina) @ 144Hz?

[zerozoneice]

Just got a Gigabyte M28U 4K 144Hz monitor with KVM switch built-in.
I have 2 issues:

- cannot get more than 120Hz using my USB-C -> DP cable
- cannot get keyboard/mouse to work on the Mac, works only on the laptop connected via USB-C -> USB-C

Keyboard/Mouse are wired, hooked up to the monitor. KVM switch should handle inputs and video when i click it.
I can get video to switch, but as i said, no keyboard/mouse on the Mac. If i plug them in the Mac, they work duhh....but not on Laptop

Questions:
- Any idea why the keyboard/mouse won't work on Mac?
- Do i need a USB-C -> DP 1.4 DSC cable to get full 144Hz and HDR @ "looks like 1920x1080" resolution on the Mini?
- Would a high speed HDMI -> HDMI 8K cable work the same? (they say 8K@60Hz, 4K@144Hz, etc..)

Thanks!

 

[Krevnik]

Questions:
- Any idea why the keyboard/mouse won't work on Mac?
- Do i need a USB-C -> DP 1.4 DSC cable to get full 144Hz and HDR @ "looks like 1920x1080" resolution on the Mini?
- Would a high speed HDMI -> HDMI 8K cable work the same? (they say 8K@60Hz, 4K@144Hz, etc..)

- DisplayPort can't carry USB, so you'd need a DisplayPort cable for video and a USB cable for data in this setup. And I'd expect there's a setting to say which input (HDMI 1/2, or DisplayPort) uses the USB-B port. Beyond stating that, there's not enough information in your post on how things are all wired up to do anything more than guess what you are missing.
- To go above 4K @ 120Hz with a single DisplayPort 1.4 link, DSC needs to be supported on the source (your PC/Mac) and the sink (the display). Something is probably preventing DSC from being detected or enabled. Hard to say what.
- The M28U's HDMI support caps out at 4K @ 120Hz. Cables won't change that.

Honestly, the difference between 120 and 144 is pretty small to my eyes. I have a 144Hz panel myself (38" UW) and just run it at 120Hz and haven't felt like I was missing anything compared to the few times I run. Especially if I can keep the framerate locked at 120fps.

 

[zerozoneice]

mmmkay, so i updated to Big Sur 11.6 and voila, i can use either cable and get full 144Hz (reported by monitor).
Did a test and swapped the cables:

- mini connected to monitor via usb-c/usb-c
- hp connected via usb-c/DP
- keyboard&mouse to monitor

Guess what, keyboard/mouse worked in Mac but not in HP laptop...
I have a USB-B port (uplink) on the M28U and included in the package an adapter for that. Hmm, should i plug it also in?

So the second device (whichever is NOT using the USB-C port), must be connected to either DP/HDMI AND to USB-B?
Now i have to install the F07 firmware on the monitor, apparently it fixes some KVM issues also, besides inputlag fix.

EDIT: so now i hooked up the Mini using USB-C -> DP AND the USB-B -> USB-A uplink cable
Keyboard/Mouse hooked to monitor. Everything works on the Mini.

As soon as the battery charges on the HP Laptop, i will try to connect using USB-C -> USB-C and it should work no? (keyboard/mouse i mean).

Another weird thing: now i can enable 144Hz and HDR. But youtube videos are not detected as HDR content.
I can swear before when i didn't have 144Hz (maybe was on 120Hz?) and HDR enabled, videos were detected as HDR.
What can be the reason? The 144Hz?

WAIT, is it the 11.6 Big Sur update which disabled/removed this feature?!
EDIT TO THIS: Yes, seems 11.6 and/or Safari 15 removed this feature. I downloaded Chrome and Youtube HDR videos play and are detected as HDR.

 

[zerozoneice]

yeah, so problem solved.
Woking setup:

- USB Keyboard/Mouse wired to monitor
- Mini M1 wired with USB-C -> USB-C
- HP Laptop wired with USB-C -> DP 1.4, as well as USB-B -> USB-A cable provided by monitor

Keyboard/mouse works fine on both devices, KVM switch button works.
Mini M1 running at 4K/144Hz (1080 HiDPI) and HDR
HP Laptop running Windows 10 at 2560x1440/144Hz and 125% scaling.

The HDR Youtube videos seems to be a Safari issue, it worked before with Big Sur 11.2, now in 11.6 not.
Using Chrome instead detects & plays fine 4K/HDR Youtube content.

Perfect.

LE: hooked a Logitech C615 camera to the 3rd USB port of the M28U monitor, guess what...i can use it perfectly in both Mac and Windows laptop. Plug & Play. Nice.