Macbook Air M3 dual monitor dock recommendation needed

MacMingHK wrote:

I tried

HP HSN-IX03 - HP Thunderbolt Dock 120W G4 USB-C + 120W AC Adapter

It doesn't work when dual monitors are connected.

HP – HP Thunderbolt Dock 120W G4

Is this the dock? If so, I think I see the problem.

According to its Technical Specifications, this dock has

• One HDMI 2.0 port
• Two DisplayPort 1.4 ports
• One USB-C port with DisplayPort Alt Mode support
• One Thunderbolt daisy-chaining port

which means that there are potentially five places where you can plug in displays.

As I mentioned before, Macs do not support DisplayPort MST daisy-chaining or the equivalent. They can drive one display over USB-C (DisplayPort Alt Mode), two over Thunderbolt. I'm guessing that this dock uses the equivalent of DisplayPort MST daisy-chaining to get some of the "extra" outputs.

If this is correct, then there might be specific pairs of outputs that WOULD let a Mac drive two external displays in an extended desktop way. The question is discovering which pairs. The Q&A's on HP's site were unhelpful in this regard – but a little Google searching turned up this Reddit thread:

https://www.reddit.com/r/MacOS/comments/1eohaio/how_to_get_an_hp_g2g4_dock_to_work_with_2/?rdt=47343

"The key is to plug one monitor into one of the two DisplayPort outputs (I have it on the bottom one), and another monitor into the Thunderbolt port on the back. #NOTE: The thunderbolt port is on the back lower right and is distinguished by the thunderbolt icon, as opposed to any of the other USB-C ports available on the dock."

So – use ONE of the two ports highlighted on the left (NOT both!), together with the port highlighted on the right (you may need a USB-C to (whatever) adapter or adapter cable for that one). Then cross your fingers and hope that the people posting to the Reddit thread were correct.

Macs only support connecting two monitors through a single dock, hub, or dual-display adapter if that device is a Thunderbolt one. They do not support DisplayPort MST daisy-chaining or its equivalent, and so will not drive two displays in extended desktop mode over a plain USB-C dock. (Unless that dock is using some sort of workaround that drives some or all of the monitors in a second-class way, with the associated compromises).

The M3 MacBook Air only supports driving two external displays when the lid is closed. That might introduce an extra complication when attempting to attach two displays through a single dock – so I would suggest checking specifications and compatibility requirements of docks you are considering very carefully.

Three long-time vendors of Thunderbolt gear for Macs are:

• Other World Computing
• SonnetTech
• CalDigit

I do not have first-hand experience with their Thunderbolt products, but based on the completeness of the product descriptions on their sites, how long they've been selling Thunderbolt products to Mac users, and the mentions of their products I've seen in reviews, they would be on my "goto" list.

MacMingHK wrote:

I have two monitors one HDMI and one DP.

Given the preceding, I'd suggest

• Connecting the DP monitor to one of the DP ports on the dock via a DP-to-DP cable
• Connecting the HDMI monitor to the Thunderbolt daisy-chaining port on the dock via a USB-C to HDMI adapter or adapter cable. (You can find these on Amazon and other sites.)

Good luck!

MacMingHK wrote:

You are awesome!

I tried this pattern and it does works!!

Although seems very silly to me as at the end as I have to have a DP -> Thunderbolt converter (which is another USB-C Dock......)

So basically I still need two docks to make it works with two monitors. very inefficient but works!!

Since at least one of your displays has a DisplayPort input, the connection to the DisplayPort can be made with a simple cable.

For the connection to the Thunderbolt port, use

• A USB-C to USB-C cable,
• A USB-C to DisplayPort adapter cable, or
• A USB-C to HDMI adapter cable

depending on what type of input your monitor needs. You don't need a Thunderbolt device, nor do you need to attach a second dock just for the purpose of using it as a video adapter.