Arch Linux

jamess7995

Member

Registered: 2021-10-25

Posts: 41

How can I use this Thunderbolt 4 expansion card, for powering a displa

I've got this new ThunderboltEx 4 asus expansion card, and it isn't plug and play. I've got it paired with an ASUS ROG STRIX Z690-A mobo. I'm trying to connect an LG UltraFine display that work gave me, I bought the expansion card for this monitor, so if it doesn't work, I'm just gonna return the card.

I know it's being detected in Arch in some capacity, if I plug in a USB TYPE-C to TYPE-A adapter, usb drives show up if I plug them in. The display, does not. I'm not sure what I'd even look for in the hundreds of lines of dmesg, I did see this bugzilla report, that talks about different hardware needing a custom kernel, and that's outside my current skill depth, and I don't know if it'd even fix my issue, having just reinstalled arch, I don't trust myself with that.
Someone on reddit suggest I check out the Arch Wiki on Thunderbolt, I didn't really get anywhere with that. I made sure plasma-thunderbolt, fwupd, and bolt are installed, they are. I added the udev rule, just in case, no change in behavior.
Is there better info I can provide, any ideas?

progandy

Member

Registered: 2012-05-17

Posts: 5,312

Re: How can I use this Thunderbolt 4 expansion card, for powering a displa

If you have the memory allocation problems for thunderbolt itself, then that seems to require the kernel patch you mentioned. https://www.reddit.com/r/Thunderbolt/co … atability/
For the graphics part I'd guess that card may also need a graphics driver that registers an output-only graphics device and that driver does not exist for linux. (see below)

Last edited by progandy (2022-03-29 19:29:41)

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Slithery

Administrator

From: Norfolk, UK

Registered: 2013-12-01

Posts: 5,776

Re: How can I use this Thunderbolt 4 expansion card, for powering a displa

Does it actually provide a display output by itself or do you have to chain your existing graphics card through it with the provided cables?
That's the only reason I can see that it would have DP inputs...

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Closing -- for deletion; Banning -- for muppetry. - jasonwryan

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progandy

Member

Registered: 2012-05-17

Posts: 5,312

Re: How can I use this Thunderbolt 4 expansion card, for powering a displa

Does it actually provide a display output by itself or do you have to chain your existing graphics card through it with the provided cables?
That's the only reason I can see that it would have DP inputs...

You are correct, but I am not sure if the card needs special driver support to switch to the mode that can send DP data as well.

https://www.asus.com/Motherboards-Compo … sk_Manual/
https://dlcdnets.asus.com/pub/ASUS/mb/A … SG_WEB.pdf

Your ASUS ThunderboltEX 4 card features two Thunderbolt™ 4 ports that support
Thunderbolt™ 4 technology, and two mini DisplayPort IN ports (support DisplayPort 1.4
specifications) that allow you to redirect VGA input signals through the ThunderboltEX 4
card for video output. The Thunderbolt™ 4 port also features a number or features such
as 40 Gb/s bi-directional bandwidth and incorporates DisplayPort 1.4 support, enabling
transfer and display of 8K video files simultaneously, and allows you to connect up to five
Thunderbolt-enabled devices in a daisy-chain configuration using Thunderbolt™ cables. The
TYPEC_1 port also supports up to 100W for laptop quick charging

Anyways, I love it that they talk about VGA signals for DP connectors.

Last edited by progandy (2022-03-29 19:34:58)

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jamess7995

Member

Registered: 2021-10-25

Posts: 41

Re: How can I use this Thunderbolt 4 expansion card, for powering a displa

You are correct, but I am not sure if the card needs special driver support to switch to the mode that can send DP data as well.

Does it actually provide a display output by itself or do you have to chain your existing graphics card through it with the provided cables?
That's the only reason I can see that it would have DP inputs...

So I did just find out on reddit that I do need to "daisy chain" it. Didn't know that, so that was promising, except, I did that, mobo intergrated graphics DP port to mini dp port 1 on the expansion card. Then Type C port 1 to lg ultrafine display, no dice, even after a reboot.
I definitely needed to do that from the sounds of it, but it doesn't seem like that was the only obstacle.
Can you guide me to finding if I even have those dmar errors mentioned, and if I do have them, where do I start for patching my kernel, that feels more intense than I feel prepared for.