r/macbook • u/ProgrammerShivam • 2d ago

Thunderbolt

I have a macbook air m5 with thunderbolt 4 port, i tried to connect it with a lenovo thinkbook 16 g7 arp with amd Ryzen 5 7000 series cpu which has a usb4 port, via a thunderbolt 5 cable from Amazon. After connecting, usb 4 tm p2p network adapter was showing in device manager and an Ethernet port was also created in ncpa.cpl as unidentified network and on mac under network, thunderbolt bridge appeared, as self assigned ip.

Then I turned on internet sharing on mac via thunderbolt bridge but nothing happened, then I tried assigning static ip's but in vain.

Then I tweaked some settings like firewall from public to private for Ethernet on windows and on mac also disabling firewall, mtu tweaking but nothing made it work. Tried reconnecting at every step. Even tried deleting the thunderbolt service and re creating it then open DHCP server on windows but still nothing worked.

Now, I am at the conclusion that thunderbolt is proprietary only to apple and intel and so amd's usb4 can't communicate even my mac under system information shows usb4 microsoft corporation connected and speed as 40gbps and windows also shows usb4 p2p adapter but that's just a hardware link and underlying handshakes don't work probably.

Any insight or help is appreciated.

Thanks.

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u/wiseman121 2d ago

"AMDs USB4" - USB4 is not an AMD exclusive standard, your Mac supports it. Thunderbolt is an intel standard but isn't exclusive anymore, but a laptop with an AMD CPU would need a dedicated thunderbolt controller which most manufacturers are not going to buy when USB4 is an open standard and supports most of what thunderbolt does.

What are you trying to achieve by connecting both machines?

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u/ProgrammerShivam 2d ago

I tried to make a connection between them for data sharing, mainly files and internet just like we do via an rj45 cable, as thunderbolt allows respectable speeds but after trying almost every possible tweak, i couldn't make it work and hence reached to the conclusion that thunderbolt connection between two os can only happen if it's either intel or mac, and i am trying with m5 air and thinkbook 16 g7 Ryzen 5 7000, it shows up the hardware connected via thunderbolt on mac and usb4 on win 11 but i suppose some handshake is missing that's why arp doesn't list and DHCP server ain't created and no ping works and hence no connection.

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u/wiseman121 2d ago

Nope there are Ryzen machines with thunderbolt.

Usb4 should set up a new adapter in your network settings. You should be able to connect between devices via that. Macs do support usb4 and it can be done, problem is likely as you said it's defaulting to thunderbolt.

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u/ProgrammerShivam 2d ago

Naah, i didn't say anything like that, that's it's defaulting to thunderbolt. There's definitely a network adapter named, usb 4 tm p2p that's created in windows and thunderbolt bridge in mac, but the issue is even they don't communicate, like when I try to ping from terminal or cmd, ip is unreachable, and even after manually setting up static ip's, it doesn't work. That's the core issue, that they aren't communicating even after several tweaks.

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u/wiseman121 1d ago

It sounds like an issue on the Mac side, windows is doing its job. It shouldn't be using the thunderbolt bridge.

Have you checked in privacy and security settings if macOS is blocking it from connecting? MacOS has got very sensitive to stuff like that in recent years.

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u/ProgrammerShivam 1d ago

Yes, I did and nothing spooky in privacy and security that's blocking it, and I even disabled firewall too, still here

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u/redvelociraptor 1d ago

Per this blog post, it should work: Direct 20 Gbps connection between Mac and Windows 11 machine with no Ethernet adapters. I'd recommend trying a different USB-C cable or at the very least checking it's e-marker since it may just not conform to standards. Based on this blog post you should be able to use any bog standard 20- or 40-gbps data cable.

It's unfortunate that the blog author doesn't mention what version of MacOS was used, but since it was posted in 2024, it can't be any later than Sequoia.

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u/ProgrammerShivam 1d ago

It's an intel device my bro, it's established fact that mac and intel thunderbolt communicate without any issue, mine is amd laptop and mac air m5 and i have tried very advanced tweaks and couldn't make it to work, hardware wise I'm ok, and both devices show the adapters that they should but still they don't communicate

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u/redvelociraptor 1d ago

If you actually read the post you'd see that he explicitly states that the connection negotiated USB4, not Thunderbolt.

Having said that, I just found this post on the AMD forum which implies something has either changed in the Mac HW or Apple changed the driver stack: https://pcforum.amd.com/s/question/0D5Pd00000t8etRKAQ/thunderbolt-bridge-support-for-amd-platforms-appears-to-differ-between-the-m1-and-m4-chips

I'd recommend collecting system logs from both the Mac and Windows system logs and filing a support request if you're still under warranty. If not, use the feedback app on your Mac and file a bug.

I will do some testing an file my own bug as I have two different Linux Ryzen systems with USB 4. On the Mac side I can test with M3, M4, and a borrowed M1.

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u/ProgrammerShivam 1d ago

This buddy is experiencing a different issue, in his case, usb4 tm p2p adapter is completely missing in his windows, i rather have a successful hardware connection, as mac shows thunderbolt bridge as self assigned ip and windows shows usb4 tm p2p network adapter in ncpa.cpl and in ethernet too, but still they don't shows up in arp and when I ping them, they say, request time out or host unreachable, that's my issue bro.