MacBook Pro M1 multi-screen issue with HDMI TV and Wacom tablet

Apple-Silicon 2020 M1 MacBook Pro and Air and similar models with M-series (plain) processors are extremely-capable entry-level computers. They can support the internal display AND an External display up to the previously unheard of size of the Apple 6K display at billions of colors. But only ONE in addition to the internal display.

This may not match the way older computers forced you to work, since older computers were not able to support a really large External display. But it is NOT a defect. The spec was available long before you could purchase the computer.

The Apple standard for its built-in hardware-accelerated displays, makes them suitable for full-motion video for production/display of cinema-quality video with NO dropped frames, and NO dropouts or partial-blank scan lines due to memory under-runs or other issues. This requires a hardware rasterizer/display-generator for each fully-accelerated display, supported by Huge memory bandwidth to refresh each display 60 or more times a second.

If you need more hardware-accelerated displays than the built-in and ONE External display, and an un-accelerated iPad if desired, you probably need a more capable computer.

On the MacBook AIR M3 (base) models with 13-in or 15-in displays, you can close that lovely display you paid dearly for, and use the display generator for a second External display, INSTEAD OF (NOT in addition to) the Internal display.

If you are doing ONLY program listings, spreadsheets, stock quotes and other slow to change data, there are some other solutions, but they require you to make some strong compromises.

Executive summary: More than ONE additional Hardware-accelerated External display can NOT be added to the entry-level 13-in or 15-in M1 or M2 or M3 or M4 systems.

If you are doing ONLY program listings, spreadsheets, stock quotes and other slow to change data, there are some other solutions, but they require you to make some strong compromises.

is that what you are doing?

These other solutions are not suitable for full-motion Video, and using a mouse on them can make you feel queasy.

none of that is full motion video for the second display.

DisplayLink technology creates a "fake" display buffer in RAM, sends the data out over a slower interface to a stunt box with DisplayLink custom chips that put that data back onto a "legacy" interface. It is not a true "accelerated" display, and it can suffer from lagging. Just adding the DisplayLink Driver is not adequate to get a picture -- you need a DisplayLink "stunt-box" or a Dock that includes DisplayLink chips.

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It may be acceptable for a second display showing slow-to-change data such as computer program listings, stock quotes, or spreadsheets, but NOT for full motion Video, not for Video editing, and absolutely not for gaming. Mouse-tracking on that display can lag, and can make you feel queasy.

In a pinch, it may even play Internet videos (as one user put it) “without too many dropped frames".

If you are only doing program listings spreadsheets, stock quotes, and other slow to change data, DisplayLink can work for you, but requires you to make some strong compromises.

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It is really nice to know that you can use a DisplayLink display if you MUST have an additional display for some of the types of data I mentioned. But that is NOT the same as the computer supporting a second, built-in, Hardware-accelerated display.

These displays depend on DisplayLink software, and are at the whim of Apple when they make MacOS changes. There have been cases where MacOS changes completely disabled DisplayLink software, and it took some time for them to recover.

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I think the Big Surprise for a lot of Hub/Dock buyers is that they thought they were getting a "real" display, but actually got a DisplayLink "fake" Display. If you got what you expected in every case, I would not use such pejorative terms to describe DisplayLink.

I'm guessing that your Wacom tablet expects, and consumes, a DisplayPort Alt Mode signal – not just a USB 3.* signal. Thus it counts as your 13" M1 MacBook Pro's one and only external hardware-accelerated display.

You could try connecting the TV via AirPlay, rather than via a cabled HDMI connection.

My understanding is that you can have a single AirPlay or Sidecar (iPad) display in addition to whatever hardware-accelerated displays your Mac supports.

AirPlay is not as good as a cabled connection. There may be a more limited choice of resolutions, and there might be some lags or artifacts. Whether that is acceptable is something that you would have to determine. However, a lot of "smart TVs" these days have AirPlay support built in, and if you have a TV without AirPlay, some of the Roku streaming sticks would be a fairly inexpensive way to add it (they're much cheaper than an Apple TV set-top box).

emanuele78687 wrote:

How about If I use a Display Port Link?

To clarify, there is no such thing as "Display Port Link".

DisplayPort is an industry standard for interfacing computers to monitors.

DisplayLink is a workaround technology for driving more displays than a computer was designed to support, over things like USB 3.* connections that were never intended to support video in the first place. Synaptics makes the DisplayLink chip sets that all of the "stunt box" vendors use, and provides the drivers that you must install on your computer to let it take advantage of these "stunt boxes."

The names may be similar, but they denote very different things.