HP G2 dock monitors not working with MacBook Pro

MacBook Pro A2141 looks up to several slightly-different MacBook Pro 16-in 2019. These have as many as four Thunderbolt-3 ports.

In general, Macs do not support multiple displays on one USB-C cable at all. In general, a Thunderbolt cable to a genuine ThunderBolt dock is required to support up to TWO displays on one Thunderbolt cable.

The HP G2 disk is a USB-C dock, and would not support two displays on a Mac in most circumstances. Windows has different standards. On a Mac, a ThunderBolt Dock would be required.

HP suggests this may be a DisplayLink device. if that is correct, with added DisplayLink software, a DisplayLink device can sometime support more displays, with strongly reduced responsiveness. Resolutions must be modest to avoid exceeding the bandwidth of a USB-C connection. DisplayLink displays are NOT suitable for Full-motion Video.

A search for "HP G2 Dock" turns up at least two results:

• HP – HP USB-C/A Universal Dock G2 . While HP claims that "this dock works with both HP and non-HP USB-A-, USB-C™-, and Thunderbolt™-enabled notebooks", it is clearly not a Thunderbolt dock. USB-A is not designed to carry video signals at all, so when you see something like "Use the included USB-A Adapter to connect your USB notebook to the dock and access your accessories and up to two 4K displays," that is a sure sign of the presence of some second-class workaround like DisplayLink. Sure enough, HP says "The dock is driven by DisplayLink."
• HP – HP Thunderbolt Dock 120W G2 . This one is a Thunderbolt dock, but it has at least four places to hook up displays: two DisplayPorts, a VGA port, and a Thunderbolt daisy-chaining port. This strongly suggests that the dock uses DisplayPort MST (which Macs do not support) to drive some of the outputs – and that there are only certain pairs of outputs that will support two monitors running in extended desktop mode on a Mac. (This issue has come up with other similar HP and Dell Thunderbolt docks before.)

There may be others, but I didn't do an exhaustive search. It appears that for HP, "HP G(whatever)" as part of the name of a dock refers to a model line, not necessarily to a single model.

俊霏 wrote:

I have a hp g2 dock and mac book pro(A2141), i connect the dock to the mac book, the mouse connetec to the dock work, but two monitory conntected to the dock now work(no signal). Does not this mac book not surport the hp g2 dock?

"No signal" would suggest that you have the "HP USB-C/A Universal Dock G2", or another one like it, that relies on the DisplayLink workaround.

DisplayLink does not take advantage of the first-class, hardware-accelerated video from your MacBook Pro. You need an external "stunt box" with a DisplayLink chip set and a special DisplayLink driver on your computer, to get any output. Either alone is not enough. You must have both the "stunt box" and the driver to get any signal.

Synaptics is the "arms supplier" who provides DisplayLink chip sets and drivers. They make their money selling DisplayLink chip sets to "stunt box" manufacturers, and most or all of those vendors then tell their customers to install drivers from the Synaptics site.

Synaptics – DisplayLink Graphics

With MST, the usual symptom is that you get video on both monitors – but it's the same video on both; and the computer only detects one of the two displays. (The dock is essentially feeding one signal to two monitors.) If your dock was a "HP Thunderbolt Dock 120W G2", you might run into that problem.