L1KVM, MBP 2019, TB4, and G9 issues

Hello all, this is my first post on the forum but have been following along since the TekSyndicate days.

Firstly, I’m incredibly thankful for this KVM as it’s been a huge time-saver when it comes to using my setup. I previously had two different set ups for my work and personal computer set ups. I really needed to downsize :sweat_smile:

I’m hoping that you all can help me figure out wtf is going wrong with my L1KVM setup. I’m gonna be as brief as i can as to save some time.

I have the Single Monitor - Two Computer 10GB USB-C version. Aside from having some random USB disconnects that i’m pretty sure are related to my USB 3 hub, it works flawlessly with my personal desktop and my personal M1 macbook pro. Here’s how I have it set up:

  • Desktop Setup: Connected normally using one Club3d DP 1.4 cable to my GPU, and one USB-C 10Gb cable. – there are no issues with this setup

    • DP cable: Club3D VESA Certified CAC-2068 DisplayPort to DisplayPort 1.4/Hbr3 Cable DP 1.4 8K 60Hz 2M/6.56ft, Black
    • USB-C 10Gb cable: CBUS 5A 100W USB-C Cable, 6.6ft USB Power Delivery (PD) Fast Charge USB 3.1 Gen2, 10Gbps Data — Compatible with PD Docking Stations, Hard Drives, MacBook Pro, Air, iPad Pro, PixelBook, 4K/5K Displays
  • Macbook Setup: Laptop is connected to a Razer TB4 dock (got a good deal on it) which is in turn connected to the KVM with a Club3d USB-C to DP cable. It is also connected by a USB-C cable from the USB-C 10Gb to the dock. – this is where i’m plagued by problems.

    • DP to USB-C cable: Club3D USB C to Displayport Cable 1.4 8K 60Hz, 4K 120Hz and Displayport to USB C bi-Directional 1.8 Meter/6 Feet HDR Support. (CAC-1557)
    • USB-C cable: CBUS 5A 100W USB-C Cable, 6.6ft USB Power Delivery (PD) Fast Charge USB 3.1 Gen2, 10Gbps Data — Compatible with PD Docking Stations, Hard Drives, MacBook Pro, Air, iPad Pro, PixelBook, 4K/5K Displays

Let’s elaborate a bit on the macbook setup. I have two different MBPs:

  • 2019 16" (i7)
  • 2020 13" (M1)

The M1 actually works with this setup essentially without flaw, with the obvious exception of “Apple gonna Apple” problems such as crashing on disconnect from the TB4 dock. Overall we’ll ignore this device; just make a note that it functions as expected; 5120x1440@120hz. Looks beautiful.

The real PITA is my 2019 work-issued laptop. Once connected via Thunderbolt 4 cable to the Razer dock, all the USB devices function with no issue. The main glaring issue is that my display is never detected. Sleep and wake doesn’t do anything, detect displays, boot with lid closed, re-seat DP to USB-C cable, nothing. The most that happens is that the G9 displays the current input port “DisplayPort1” up a the top right.

The next order of business was to re-seat the thunderbolt 4 cable into different ports on the mac. This also resulted in no change. “OK” i thought, "i’ll change out the Club3d USB-C to DP cable for a known working USB-C to DP adapter, and couple that with a Club3d DP 1.4 cable. This also returns the same results.

  • USB-C to DP adapter: USB C to DisplayPort Adapter 8K 60Hz, Maxonar Thunderbolt 3 to Display Port Cable with 1.4 Alt Mode Video Converter - HBR3/DSC/HDR for M1 MacBook Pro, iPad Pro, Surface Book, Dell XPS More-Grey

Up next was to clear the System Management Controller (SMC) on the macbook. This is a unique capability for intel-based macs that can fix issues with thunderbolt/displays. Unfortunately this also yielded no results.

At this point i was convinced that it could be a thunderbolt issue so i then purchased a TB3 dongle/dock to try that. Upon connecting the dongle directly with a displayport cable to the monitor i am greeted with a display, but it is only a 3440x1440@60 resolution, which is essentially unusable on the G9. this is probably just a limitation of the dongle.

  • dongle/dock: Cable Matters Triple Monitor USB C Hub (USB C Dock) with 3X DisplayPort, USB-A and USB-C, Gigabit Ethernet, and 100W Charging - Thunderbolt 3, Thunderbolt 4, USB4 Compatible for Surface Pro, XPS

To eliminate some things, i tried connecting the mac directly to the monitor with the Club3d USB-C to DP cable. This gives no display. Next i tried the USB-C to DP adapter directly, which also gives no display.

Given the steps i’ve pretty much worked it back to the laptop itself. Strangely, however, i did have the USB-C to DP adapter working with the G9 prior to the KVM – with full 5120x1440@60. The unfortunate news is that i can’t replicate this setup as one of my previous troubleshooting steps was to update from Big Sur (was working on this version) to Monterrey (the current, and non-functional version).

If there is anyone out there that could possibly give me any steps to try or is thinking of a troubleshooting method that i haven’t thought of yet, please let me know. I’m pulling my hair out trying to get this setup to work. i’m open to hop on a discord call or whatever to try and figure this out.

And as i’m submitting this i realize that i can’t put in links so i guess i’ll switch them out for the exact product name listed on amazon so you can pull them up if need be.

yay!

Try a moshi bi-directional USBc to DP cable. I do testing with the caldigit TS3 and have a samsung g9 neo. Until the 1008 firmware, the g9 neo was buggy AF almost all the time even without the kvm under different scenarios.

I’ve had best luck with moshi bidirectional cables with 2017/2019 intel mbp.

I don’t care for cable matters stuff. It used to be fine but the last year or so seems like it has had a decline in quality. I have some great cable matters cables from before then though! so frustrating.

club3d also changed their usbc to dp cable recently. It used to do really well with sleeps but one I just ordered off amazon because of another customer report and I was able to reproduce an issue with it whereas moshi continues to be ok. finally if you can use short club3d cables like 3 foot DP to DP when the dock is involved, that helps too. That’s what I use with the ts3+ dock for the DP output.

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Thanks for your reply @wendell. I greatly appreciate the follow through when supporting customers. I’m sure deciding to release hardware was not an easy one considering it opens the door to fielding questions such as mine.

Although I don’t strictly need both cables for my scenario, I will order both the club3d 3ft and the moshi bidirectional usbc to dp cable. and even if this journey has been quite the money pit, i just want a setup that works the way i expect when sitting down to work or play games.

anyways i’ll order these and give em both a shot. either way i’ll be following up with a post here.

No prob. The apple tax in r&d is about 10x too so enjoy the schadenfreude of that if you like haha

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haha as they say “better you than me” :stuck_out_tongue:

i’ve ordered one of each of the following:

  • Moshi USB C to DisplayPort Cable 1.5m/5ft, Support 5K@60 Hz, 4K HDR, VESA Certified, Aluminum Housing, Thunderbolt 3 Compatible (Ensure Monitors Accept DisplayPort Signal)
  • Club3D CAC-2067 DisplayPort to DisplayPort 1.4/Hbr3/ HDR Support Cable DP 1.4 8K 60Hz 1 Meter/3.28 Feet Black Vesa Certified

tried all manners of cable configurations today. as it turns out (as a surprise to nobody) the razer dock is the issue.

the dock is not outputting any video directly to the monitor, having removed the KVM from the equation.

i’ve never had a single razer product that i’ve had a good experience with. i’m never going to buy another one of their products ever again, even if they are on sale for 100 bucks off.

that brings me to my next question @wendell … what dock would you recommend?

I test with the caldigit ts and ts3+

the dell dual usbc/thunderbolt dock can also work well but not sure about the mac side.

you might try doing the pram reset or reboot the mac after config changes because it stops trying sometimes.

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I’m using CalDigit USB-C Pro dock with two display ports (has a hdmi version too), works great, it’s thunderbolt not usb-c, but works with usb-c too, but usb-c mode 4k 30hz, not 60hz

Michael over at Phoronix just reviewed this unit. It is USB-C.

It may not have all of the connectivity that you are looking for though.

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