Catalina causing issues with HDMI

[rehkram]

I just retried the HDMI to HDMI connection from my mac mini 2018 running 10.15.3. It is now working. Monitor is a Samsung U32J59x, cable is plugged into the monitor's HDMI-2 port. Here's the system report:

Intel UHD Graphics 630:
Chipset Model: Intel UHD Graphics 630
Type: GPU
Bus: Built-In
VRAM (Dynamic, Max): 1536 MB
Vendor: Intel
Device ID: 0x3e9b
Revision ID: 0x0000
Metal: Supported, feature set macOS GPUFamily2 v1
Displays:


U32J59x:
Resolution: 3840 x 2160 (2160p/4K UHD 1 - Ultra High Definition)
UI Looks like: 3840 x 2160 @ 60 Hz
Framebuffer Depth: 30-Bit Color (ARGB2101010)
Display Serial Number: HTPM403195
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Adapter Type: DVI or HDMI
Automatically Adjust Brightness: No
Adapter Firmware Version: 2.16

So I left the mini plugged-in to HDMI-2 and plugged in my rMBP mid-2012's HDMI port to the monitor's other HDMI port, HDMI-1, to see if I could switch back and forth between the two sources using the monitor's on-screen display. To my mild surprise it is working but only at 30 Hz which I assume is a limitation of the rMBP 2012 since I swapped the two m/c's input ports and still only got 30 Hz

It's been solid for all of half an hour will have to see how reliable it is over time.

I just mention this in case anyone that is using the workaround, USB-C to DisplayPort- or HDMI, wants to give HDMI to HDMI another shot. I did not reboot the mini or the monitor, just pulled the workaround cable and plugged in two HDMI cables I had laying around. I then used monitor's on-screen display to flip-flop between the two HDMI input sources.

Bonus test: the rMBP Lightning to DisplayPort connection resulted in a broken-up mess, did not work while the HDMI was active on the mini side. Could be the m/c, the cable or the monitor, I don't know.

If anything changes re. reliability I'll post an update.

 

[ariandax]

Same - incredible issues here...
mac mini 2018 + lg oled 77 "
What i did:

1. Changed hdmi/hdmi cable/port tv
2. Switch to usb-c to hdmi adapter
3. (today i'll test for usb-c to hdmi cable)
4. Switch on and off the lg hdr setting (warm color)

If i try to adapt resolution, mini switch off and on the tv...while i'm working normally on mac, suddenly the oled switch off, then i have to manually switch on by tv remote....

incredible nervous...

whatttttt damn i can do?!?!?!

 

[semdi]

I'm having the same issue. I have a iMac 5K 2017, and an ASUS 2K monitor hooked up via HDMI to HDMI, through an apple Muti-connector to usb-c. when the computer wakes up or restarts, the iMac brightness shoots to full brightness. anyone else experience this. Will a display port to usb-c fix this?

 

[Feocalatrava]

THIS WORKED FOR ME!

I used SwitchResX in my Mac Mini (Late 2012) + a 47-inch Philipps TV with an HDMI - HDMI cable.

I'm running MacOS Catalina 10.15.3 and I since this app worked for me I think it may work for others experiencing the same issue as well.

It dind't work out-of-the-box, but it did after changing the settings in the app and finally it got it working.

I hope it helps!

 

[Dave_O]

Just updated to Catalina 10.13.4 on 2018 Mac Mini. HDMI FW updated from 2.16 to 2.19. Hope this fixes the occasional blank boot screen.

 

[bwinter88]

After the 10.15.4 update I'm getting a weird pink artifact around blue links on google search. Anyone else getting this?

As I look around my desktop, all the text looks kind of smudgy, in fact.

I'm on a 4K TV via HDMI on a Mac Pro w/ Vega II Duo.

EDIT: Disabling the HDR option in Display settings fixed this.

 

[deja_geek]

I have tried this adapter with success on my 24” 4K LG computer monitor. This adapter resolves my HDMI issued on both of my 4K screens.

Belkin USB-C to HDMI Adapter

Belkin USB-C to HDMI Adapter

The Belkin USB-C to HDMI Adapter effortlessly connects your USB-C enabled Mac to your HDTV or HDMI-enabled display. Buy online now at apple.com.

www.apple.com

Like many on this thread, I was having the same issue of no HDMI when starting up my Mac mini. I also have a LG 4K monitor. Switched to a USB C to Display port cable and that didn't resolve my issues. Then I came across this thread. Upon the recommendation of the quoted posted, I bought one of the Belkin USB-C to hdmi adapters and it completely solved the issue of not having HDMI on boot. I seriously either had to reset the PRAM every boot or boot it into recovery mode/reset password to get my display going. Now here is my tip for everyone reading this. Don't shell out over $50 for a white Belkin adapter through Apple, when you can get the exact same adapter on Amazon for roughly half:

Belkin USB-C to HDMI Adapter, Works with Chromebook Certified(Supports 4K @60Hz, HDMI to USB-C Adapter, USB Type-C to HDMI Adapter), Black (F2CU038btBLK)

The USB-C to HDMI adapter provides a smooth and effortless experience for connecting your USB-C-enabled device to your HDTV, 4K/Ultra HDTV, or any other HDMI-enabled display . This adapter supports 4K at 60Hz, providing stunning clarity and sound For the ultimate viewing experience. This product ...

www.amazon.com

Like I said before, this adapter solved my issue of not having HDMI or my display turning on at boot.

One thing to note, and I came across this information after making the post. The white adapter (sold through Apple) also supports using it to connect a monitor to the iPad Pro. It also supports Dolby Vision for HDR on monitors that have that feature.

 

[Superhai]

After the 10.15.4 update I'm getting a weird pink artifact around blue links on google search. Anyone else getting this?

This is because of chroma subsampling, you are most likely not running RGB color format on the HDMI anymore because of bandwidth limitations and display is switched to YCbCr422 or similar. Usually there are settings in the TV if it is capable of full RGB with 4k HDR.

Actually 90% of HDMI issues are because of bandwidth. As HDMI2.0 and HDMI Cat 2 cables are over their limits for the 4k full RGB 60hz 30bit that a Mac tries to chow into the TV. The cable need to be perfect (most off the shelf cables work fine for 4k HDR 60hz, but not with RGB) and as short as possible. HDMI2.1 and Cat 3 cables will solve this.

 

[tk_mac]

Upon the recommendation of the quoted posted, I bought one of the Belkin USB-C to hdmi adapters and it completely solved the issue of not having HDMI on boot.

Which version of Mac OS are you on now with this workaround? I am still on 10.15.2. Should I update? Will the workaround still work? Will I be able to use the Mac Mini 2018's real HDMI port and put my dongle aside?

 

[Dave_O]

Since updating to 10.15.4, I have not had a single instance of the problem with my 2018 Mac Mini connected to a Samsung 4K TV as a monitor. The HDMI handshake is also visibly different on boot.

 

[tk_mac]

Since updating to 10.15.4, I have not had a single instance of the problem with my 2018 Mac Mini connected to a Samsung 4K TV as a monitor. The HDMI handshake is also visibly different on boot.

Are you connected directly HDMI port on computer to HDMI port on monitor, without adapters? (Can I get rid of my workaround USB C to HDMI adapter if I update Mac OS?) What Mac OS version are you on?

 

[Dave_O]

Yes, HDMI -> HDMI, no adapters. Catalina version 10.15.4

 

[deja_geek]

Which version of Mac OS are you on now with this workaround? I am still on 10.15.2. Should I update? Will the workaround still work? Will I be able to use the Mac Mini 2018's real HDMI port and put my dongle aside?

I am on 10.15.4, but I have not tried it without the adapter. The adapter also allows me to control the brightness of my LG monitor using keyboard buttons/shortcuts. There is something with the way HDMI is implemented on the Mini's that breaks DDC/CI standard. I'm using this app, https://www.nesveda.com/projects/ExternalDisplayBrightness/ and there is a brief overview of the issue at the bottom of the compatibility section. So I don't know if I will stop using the adapter.

 

[tk_mac]

Since updating to 10.15.4, I have not had a single instance of the problem with my 2018 Mac Mini connected to a Samsung 4K TV as a monitor. The HDMI handshake is also visibly different on boot.

Yes, HDMI -> HDMI, no adapters. Catalina version 10.15.4

I updated my 2018 Mac Mini to 10.15.4 and added the supplemental update. I find I still have to use the dongle to get reliable HDMI output to my Samsung 4K TV. It seems that Apple hasnt fixed anything that I can tell on this issue.

 

[Dave_O]

The only other thing I did was the SMC/NVRAM reset dance after the upgrade, with the TV powered on.

 

[Stas_R]

I had bought Mac mini 2018 few days ago and connected it to Samsung SyncMaster s22b300 using hdmi-hdmi cable plugged into "hdmi switch". My hp elitebook was plugged into the same switch.
All this worked good before I turn off elitebook - Samsung become black. I turned elitebook again and Mac mini found Samsung again.
Now it is the only way for using Mac mini's hdmi port. Mac does not found Samsung when it plugged in the port. It works only plugged through the switch. And Elitebook must be plugged into the switch too and must be turned on. System information shows that driver version is 2,19.

My English is very weak. I'm sorry.

 

[tgoecke]

Solved: setting the display to DisplayPort Version 1.2 helped - now HDMI HDMI connection working on Mac mini 2018

 

[tk_mac]

Solved: setting the display to DisplayPort Version 1.2 helped - now HDMI HDMI connection working on Mac mini 2018

How or where did you set the DisplayPort Version?

 

[tgoecke]

How or where did you set the DisplayPort Version?

in settings menu of display - LG 27UL850, in addition switched offHDMI ULTRA Deep Color.
realized, that display was working only at 30 Hz
did NVRAM reset and display reset to factory settings (not for the first time)

Odd: now I can switch on
DisplayPort Version 1.4 and
HDMI ULTRA Deep Color.

HDMI to HDMI @ 60Hz works in 4k

really confusing

 

[tommiy]

I reverted back to Mojave because of the DisplayPort issues with Catalina. Mojave did not experience the issues that Catalina has. The System report for thunderbolt and the displays are misleading as they are inaccurate and may not represent the actual connection to the device if you are using a Thunderbolt/USB connection to the device. If you run AGDCDiagnostics you can see that at times Catalina decides to overwrite the Max Line Rate that a connected device can support, or at least in my configuration. The devices themselves have not changed. I've provide Apple outputs of Mojaves well behaving dealings with connected devices and that of Catalina. With Catalina, it will typically reduce the max line rate to HBR meaning that your into low res mode. I have demonstrated to apple that Catalina typically will take HBR2 connected devices and move them to HBR if there is any negotiation required on the connection. Anyway, Mojave is unfortunately the last version that seems to be well behaved. @joevt assisted me with this a long time ago as he has way more knowledge in this area than myself. I rolled back to Mojave and don;t miss the hype of Catalina or BigSur because I'd rather have a stable and functional mac. I'm not sure that Apple have the knowledge or expertise to fix this. Its persisted for a very long time.

 

[Alameda]

in settings menu of display - LG 27UL850, in addition switched offHDMI ULTRA Deep Color.
realized, that display was working only at 30 Hz
did NVRAM reset and display reset to factory settings (not for the first time)

Odd: now I can switch on
DisplayPort Version 1.4 and
HDMI ULTRA Deep Color.

HDMI to HDMI @ 60Hz works in 4k

really confusing

The display can support HDMI 4K30 Deep Color or 4K60 without Deep Color. Deep Color means RGB/4:4:4 10-bit or 12-bit color.