Thunderbolt 2 to HDMI Problem

[woodsky]

I have a 2014 MacBook Pro with both hdmi and thunderbolt 2 ports.
I recently purchased a minidisplay to hdmi cable hoping to connect to a Dell external monitor.
However it doesn’t work when I plug it in the monitor did recognize that something has plugged in and tried to switch to the input but all I get is a blank screen.
I decided to post it here hope someone can give me some advice.
Here’re couple things that I noticed when trying to figure out on my own.

•I connected this cable to an older monitor which has 1 HDMI port and 1 VGA port and it worked flawlessly. So that tells me the cable is ok and my MacBook with it’s thunderbolt port is ok.
•I then used a hdmi cable to connect the MacBook and Dell monitor on their hdmi ports and still worked fine. Now that I know the hdmi on my monitor isn’t broke either.
•I also reset the PRAM on my MacBook but no luck from there.

 

[Juicy Box]

For clarification:

Are you trying to use a TB2 port on your MBP to connect to a monitor with HDMI?

Or

Are trying to use the HDMI port on the MBP to connect to a monitor with Mini Display Port?

If it is the latter, then you will need a special cable, as HDMI to MDP will not work with a standard HDMI/MDP cable.

 

[joevt]

Which Mini DisplayPort to HDMI cable did you use?
Which Dell display is it?

Did the MacBook Pro detect the display? What resolutions does it show? Are you using a second display to see this, or are you using Screen Sharing?

 

[woodsky]

For clarification:

Are you trying to use a TB2 port on your MBP to connect to a monitor with HDMI?

Or

Are trying to use the HDMI port on the MBP to connect to a monitor with Mini Display Port?

If it is the latter, then you will need a special cable, as HDMI to MDP will not work with a standard HDMI/MDP cable

I know it's a bit messy
It's the first one, TB2 on MBP to HDMI on monitor. What's bothers me is that everything seem to working properly on individually but once I connect them together they stopped working.

 

[woodsky]

Which Mini DisplayPort to HDMI cable did you use?
Which Dell display is it?

Did the MacBook Pro detect the display? What resolutions does it show? Are you using a second display to see this, or are you using Screen Sharing?

1. It's a Primecable brand mini DP to HDMI it specifically says on the package it's for apple devices
2. monitor is S3220DGF

My Macbook pro doesn't show the secondary display preference screen basically no signs of connection. However the cursor responds to my trackpad input was very slow the moment I plugged in the connector and gets better after a few seconds.
I also have dell monitor connected to my PC via full-size displayport and when I connect my macbook to the monitor, it switch itself to HDMI input but displays nothing.

 

[joevt]

The Dell S3220DGF has a DisplayPort input. Why not use that? Because you are connecting two computers to the same display? Can the PC use HDMI instead of DisplayPort?

The 2014 MacBook Pro has an HDMI output. Why not use that?

Which 2014 MacBook Pro do you have? I suppose it shouldn't matter. The 13 inch and 15 inch should both be able to do 2560x1440 60Hz from DisplayPort or HDMI.

Maybe you need an active DisplayPort to HDMI adapter. The Primecable adapter is probably passive (do you have a link?). The CAC-1180 should work. It may be overkill since it supports DisplayPort 1.4 and HDMI2.0b (HDR) but that just makes it more future proof. In that case, the CAC-1085 is even more future proof (there's no CAC-1185 for Mini DisplayPort, so you would need a Mini DisplayPort to DisplayPort adapter like the CAC-1110).

 

[woodsky]

The Dell S3220DGF has a DisplayPort input. Why not use that? Because you are connecting two computers to the same display? Can the PC use HDMI instead of DisplayPort?

The 2014 MacBook Pro has an HDMI output. Why not use that?

Which 2014 MacBook Pro do you have? I suppose it shouldn't matter. The 13 inch and 15 inch should both be able to do 2560x1440 60Hz from DisplayPort or HDMI.

Maybe you need an active DisplayPort to HDMI adapter. The Primecable adapter is probably passive (do you have a link?). The CAC-1180 should work. It may be overkill since it supports DisplayPort 1.4 and HDMI2.0b (HDR) but that just makes it more future proof. In that case, the CAC-1085 is even more future proof (there's no CAC-1185 for Mini DisplayPort, so you would need a Mini DisplayPort to DisplayPort adapter like the CAC-1110).

I’m using Displayport for my PC since I’m running it at 165hz and 10bit color.
I definitely can use HDMI on the MBP however the DisplayPort is on the same side with MagSafe I’d like it to have cables not all over the place.

here’s the link for my cable

PrimeCables® Mini DisplayPort to HDMI Adapter Cable Gold Plate 10ft

PrimeCables® Mini DisplayPort to HDMI Adapter Cable Gold Plate 10ft

www.primecables.ca

What bothers me is that this cable works totally fine on my other monitor, I can’t see any logical reason why it wouldn’t work on this Dell monitor since it’s HDMI port works perfectly fine at the same time.

 

[joevt]

I’m using Displayport for my PC since I’m running it at 165hz and 10bit color.
I definitely can use HDMI on the MBP however the DisplayPort is on the same side with MagSafe I’d like it to have cables not all over the place.

here’s the link for my cable

PrimeCables® Mini DisplayPort to HDMI Adapter Cable Gold Plate 10ft

PrimeCables® Mini DisplayPort to HDMI Adapter Cable Gold Plate 10ft

www.primecables.ca

That page says it supports 1080p. Doesn't mention 1440p.
Input: Mini DisplayPort 1.1a - this should be sufficient for 1440p.
Output: HDMI 1.3b - this should be sufficient for 1440p.
Bandwidth: 225MHz / 6.75 Gbps per channel - 1440p 60Hz requires ≈ 241 MHz / 7.23 Gbps (includes 8b/10b overhead)

Even if it was a bandwidth problem, it should connect and let you choose 1080p.

I can't tell if the cable is active or passive (passive requires DisplayPort Dual Mode support). The output of the AGDCDiagnose command will have the info but only if it reports the Connections which might not happen for old GPUs or NVIDIA GPUs.
/System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS/AGDCDiagnose -a > AGDCDiagnose_a.txt 2>&1
If the output doesn't include a list of Connections then a newer Mac or an eGPU is required to get the info.

What bothers me is that this cable works totally fine on my other monitor, I can’t see any logical reason why it wouldn’t work on this Dell monitor since it’s HDMI port works perfectly fine at the same time.

It's a mystery. It may be interesting to compare the EDID of the display's HDMI port using the two connection methods: using HDMI to HDMI cable, and using DisplayPort to HDMI cable. If the AGDCDiagnose output doesn't include the EDID, then you can get it from the io registry or from SwitchResX (but only if the display connects).