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M1 Thunderbolt 4 Wierdness
#57025 11/21/20 12:16 AM
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I have see this on two different M1 Mac minis. The four Thunderbolt 3 ports on the 2018 Mac mini have been replaced with two Thunderbolt 4 ports. Theoretically that would be okay as the Thunderbolt 4 standard requires Thunderbolt 4, like Thunderbolt 3, can be daisy chained and unlike TB3 it can also be distributed like USB 2, 3.0, and 3.1 and is supposedly backward compatible. The reality I am encountering is…
  • I can't find any certified Thunderbolt 4 cables or hubs (a phone call to OWC indicates they may have some shipping by mid-December)
  • Connecting the TB4 port on an M1 device to a TB3 port using TB3 cable the connection stops at the first connected device and does not daisy chain.
  • The same connected devices using the same ports and cables daisy chain correctly if the first device is a TB3 port on an 2018 Mac mini.
  • Thunderbolt 2, 3, and 4 connectors are active with sophisticated electronic circuitry and hardware.
  • OWC's TB4 cables are limited to 0.8M (29 inches) and expectations are all TB4 cables will be costly.

My question is will the TB4 daisy chain always terminate at the first non-TB4 device?


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Re: M1 Thunderbolt 4 Wierdness
joemikeb #57037 11/21/20 06:31 PM
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Don't have an answer, but I'm sure with time and more people exposure to the hardware, you will have one. In the meantime, is there such a thing as a TB3 to TB4 adapter? I know you say it is backward compatible, but the adapter would make it a "permanent" downgrade. Not desirable if the first device is TB4. Your second bullet point may accomplish this, but then again, is an adapter different circuitry?


On a Mac since 1984.
Currently: 27" iMacs, Macbook Air, macOS 10.15.x,; iPhones, iPods and iPads galore!
Re: M1 Thunderbolt 4 Wierdness
Ira L #57044 11/21/20 11:26 PM
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Originally Posted by Ira L
In the meantime, is there such a thing as a TB3 to TB4 adapter? I know you say it is backward compatible, but the adapter would make it a "permanent" downgrade. Not desirable if the first device is TB4. Your second bullet point may accomplish this, but then again, is an adapter different circuitry?
Theoretically the circuitry in a TB4 device connector is supposed to recognize a TB3, TB2, USB4, USB 3.1 GEN 3, USB 3.1 GEN 1M USB 3.0, USB 2.0 connection. In other words TB4 is in essence, an adaptor, the long term goal being a type C connector would be compatible with all existing USB/TB protocols. For now port adaptors will be necessary to connect to existing port architectures. But if you connect a TB4 port to a TB3 port it will not give the TB3 device the additional TB4 capabilities of 100W power delivery, and the ability to be distributed through a hub, nor would it make a USB 2 device capable of 40Gbps speeds.

My assumption (I know, bad word) has been that since both TB4 and TB3 can be daisy chained[, a connection originating with the TB4 port on my M1 Mac mini should be capable of daisy-chaining through the TB3 ports on my LG 4K monitor, although it would be TB3 from that point on. The signal is terminating at the monitor and does not propagate to the outgoing TB3 Type C port or any of the three USB 3.1 gen 1 Type C ports. This could be the fault of either the TB3 cable between the Mac and the monitor or the TB3 port on the monitor itself. Without a TB4 cable I have no way of testing further, and what I am reading about TB4 is ambiguous.

Last edited by joemikeb; 11/21/20 11:28 PM.

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Re: M1 Thunderbolt 4 Wierdness
joemikeb #57049 11/22/20 09:41 PM
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PROBLEMS IDENTIFIED

Some additional experimentation, switching connections around, carefully reading the tech specs has identified the following:
  1. The TB4 ports on the M1 SoC do daisy chain 👌
  2. The daisy chain persists through TB3, TB2, and Firewire devices 👌
  3. The M1 SoC simultaneously supports up to two displays: One display with up to 6K resolution at 60Hz connected via Thunderbolt and one display with up to 4K resolution at 60Hz connected via HDMI 2.0 👋
  4. I have two Thunderbolt displays 👎
  5. I really like having two displays 👍
  6. I really need the additional USB 2.0 type A ports and the FW800 port on the Apple Thunderbolt display. 🙏
  7. SoftRAID is in beta for intel processors, but will neither load nor install on M1 SoC. 🤬


POTENTIAL SOLUTIONS
  1. a new hdmi monitor ($130 to $190) I really didn't want to spend 😢
  2. a TB 3 firewire dock to provide additional USB 3.0 type A ports and FW800 connectivity (I have one in my collection) 👍
  3. an OWC Thunderbolt 4 hub to provide additional Thunderbolt 2, 3, & 4 connections for my growing collection of drives with TB3 and USB 3.1 gen 2 Type C connectors ($150 I had already planned on spending, but not yet available.) 🤨
  4. at least two certified TB4 0.5 to 0.8 Meter cables (estimated $60 each when available) 😳


CONCLUSION:
  • Moving to Apple silicon is more costly than I had initially anticipated.


joemikeb • moderator
Re: M1 Thunderbolt 4 Wierdness
joemikeb #57059 11/23/20 06:19 PM
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So are you saying the second Thunderbolt monitor maxed out the TB4 capabilities?


On a Mac since 1984.
Currently: 27" iMacs, Macbook Air, macOS 10.15.x,; iPhones, iPods and iPads galore!
Re: M1 Thunderbolt 4 Wierdness
Ira L #57062 11/23/20 07:52 PM
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Originally Posted by Ira L
So are you saying the second Thunderbolt monitor maxed out the TB4 capabilities?

To be specific on the Mac mini...
Originally Posted by Apple
Simultaneously supports up to two displays:
One display with up to 6K resolution at 60Hz connected via Thunderbolt and one display with up to 4K resolution at 60Hz connected via HDMI 2.0

Thunderbolt 3 digital video output supports
Native DisplayPort output over USB‑C
Thunderbolt 2, DVI, and VGA output supported using adapters (sold separately)

HDMI 2.0 display video output
Support for one display with up to 4K resolution at 60Hz
DVI output using HDMI to DVI Adapter (sold separately)
So although the computer can drive two displays, one of those must be HDMI and the HDMI signal may be carried via one of the two Thunderbolt ports or by the HDMI port built into the Mac itself.

The identical M1 SoC on the MacBook...
Originally Posted by Apple
Simultaneously supports full native resolution on the built-in display at millions of colors and:
One external display with up to 6K resolution at 60Hz

Thunderbolt 3 digital video output
Native DisplayPort output over USB-C
VGA, HDMI, DVI, and Thunderbolt 2 output supported using adapters (sold separately)


joemikeb • moderator
Re: M1 Thunderbolt 4 Wierdness
joemikeb #57073 11/24/20 06:19 PM
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MORE DIFFERENCES:

The more experience I have with the M1 Mac mini the more subtle but important differences I find between it and the Intel based Macs.

KEXT INSTALLATION
I just installed the new Rogue Ameoba ACE beta kernel extension and it turned into a thirteen step process:
  1. Run Installer Rogue Ameoba installer
  2. Open System Preferences > Security & Privacy
  3. Click padlock and enter administrative password
  4. Click on Restart button in the Security & Privacy window and wait for complete shutdown
  5. Press and hold power button[b] until progress bar appears
  6. Select admin account and enter password
  7. Change Security Setting
  8. Restart
  9. Enter password (system Preferences > Security & Privacy appears)
  10. Click on padlock and enter password
  11. Approve Kext installation
  12. Restart
  13. Quit System Preferences


As near as I can tell pressing and holding the Power Button is the M1 equivalent of ⌘R on Intel Macs but it went into the M1 equivalent of the T2 settings because

[b]SHOW EMOJI & SYMBOLS

Control+Command+Space (∧⌘␠) no longer opens Emoji & Symbols that is now done by the Fn key.

Last edited by joemikeb; 11/24/20 06:25 PM. Reason: finish what I started

joemikeb • moderator
Re: M1 Thunderbolt 4 Wierdness
joemikeb #57074 11/24/20 06:35 PM
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joemikeb • moderator
Re: M1 Thunderbolt 4 Wierdness
joemikeb #57075 11/24/20 07:10 PM
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Without getting deeply into investigation, that sounds like the procedure outlined in an Apple doc to which Mike Bombich linked me, which I had, in fact, intended to experiment with eventually.

I wonder if the procedure can be avoided by installing ACE from a different volume? (Update: A quick look with Pacifist suggests that it can't be done.)

I don't understand how the part about command-control-space fits in.


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Re: M1 Thunderbolt 4 Wierdness
artie505 #57082 11/25/20 02:28 PM
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Originally Posted by artie505
I wonder if the procedure can be avoided by installing ACE from a different volume? (Update: A quick look with Pacifist suggests that it can't be done.)
That would be a quick way to render Big Sur unbootable. It has to be inserted by the installer then there is a routine that is automatically run from the Recovery Assistant that I believe patches the boot image. I didn't mention it because it required no intervention or interaction on my part.

Quote
I don't understand how the part about command-control-space fits in.
It is a separate issue/change/difference between Intel and M1 Macs.

Last edited by joemikeb; 11/25/20 02:30 PM.

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Re: M1 Thunderbolt 4 Wierdness
joemikeb #57084 11/25/20 11:35 PM
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BOOT OPTIONS ON M1 MACS

I am going to attempt to walk through this but it is a bit baroque.
  1. The various Startup key combinations we all knew so well on Intel Macs do not work on Apple Silicon
  2. The only functional startup key is the power button
  3. To access any startup options of functions you have to begin from M1 Mac that has been powered down for at least ten seconds. In other words, you cannot simply reboot.
  4. Simply press the power button and continue to hold it. A note will appear on the screen to continue holding the power button to access the boot options. Then a note will appear that the boot options menu is loading and a progress bar appears. You can now release the power button.
  5. Unless the shut down was originated from System Preferences the options menu will appear. This is the familiar Option boot listing all of the bootable volumes attached to the system plus a Gear icon labeled Options.
  6. To start in Safe Mode Press and hold the shift key and click Continue is Safe Mode
  7. Clicking Options takes you to the Recovery Assistant we are familiar with
  8. Clicking a bootable volume boots you from that volume
  9. If the preceding shut down was triggered by a selection in System Preferences you will be taken directly to the Recovery Assistant and into a specific function. For example setting the Security Policy. NOTE: on Intel Macs the T2 Security policy setting was the same for every bootable volume attached to the system. On M1 Macs when you set the security policy you are prompted to choose which boot volume's security policy you are setting.


SIDENOTE: one thing I have noted in performing multiple re-installs while playing testing, the added speed of the M1 processor reduced the install time by almost ½.


joemikeb • moderator
Re: M1 Thunderbolt 4 Wierdness
joemikeb #57093 11/26/20 06:37 PM
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While the startup key combos may have been ingrained in some of us, it seems simpler with the power button and an options menu. Also, very encouraging to hear about the speed increase, at least with installs. Thanks for sharing your trailblazing experiences. smile


On a Mac since 1984.
Currently: 27" iMacs, Macbook Air, macOS 10.15.x,; iPhones, iPods and iPads galore!
Re: M1 Thunderbolt 4 Wierdness
Ira L #57096 11/26/20 09:05 PM
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Originally Posted by Ira L
While the startup key combos may have been ingrained in some of us, it seems simpler with the power button and an options menu. Also, very encouraging to hear about the speed increase, at least with installs.
I concur about the Power button. I am always looking up the various key combos because they aren't used enough to set them in my memory and, as I have said before, some of them work better if you have three arms and at least that many hands. 😉

I have one very minor gripe though, the TotalMount® under-desk mount for my Mac mini was designed with the power button on the left rear corner. On the M1 Mini it is on the upper right rear corner. The modifications to the mounting bracket necessitated the use of a ⅜ drill and a 13mm drill bit followed by cleanup work with a carbide grinder bit. Fortunately my woodworking shop is well equipped for such exigencies. Now comes the hard part, organizing and hiding the rats nest of connector and power wires on top of and below my desk. With the cooperation of Amazon and OWC I will hopefully have the don by Monday.


joemikeb • moderator
Re: M1 Thunderbolt 4 Wierdness
joemikeb #57157 12/02/20 07:33 PM
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Originally Posted by joemikeb
My question is will the TB4 daisy chain always terminate at the first non-TB4 device?

I believe that is the case, yes. The non-TB4 device does not know how to negotiate a downstream daisy chain.

Additionally, if you're running video (mini Display Port) over ThunderBolt, the video device must, if I recall correctly, always be the last device in the chain.


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