Patches Ready For Getting DisplayPort Over USB Type-C Working For More Intel Hardware

[phoronix]

Phoronix: Patches Ready For Getting DisplayPort Over USB Type-C Working For More Intel Hardware

Red Hat's Hans de Goede continues doing a commendable job improving the Linux support for various laptops with key improvements. One of the latest efforts by this longtime kernel developer has been about getting DisplayPort over USB Type-C connections working for more Intel hardware...

https://www.phoronix.com/scan.php?page=news_item&px=Hotplug-Notify-DP-Over-Type-C

[Developer12]

Is this for USB 4.0? Thunderbolt? Saying USB type-C is almost meaningless at this point.

One of the things I hate most about the current landscape is that somebody at intel thought it was a good idea for thunderbolt to require an extra cable and motherboard header. Supposedly these carry displayport and a bunch of (BIOS configured?) GPIO pins.

Suddenly I can only have thunderbolt if my motherboard supports the header and I buy a motherboard-specific card. At that point, why not put it on the motherboard? Why support cards at all?

It should have been PCIe-only. Put a DP input port on the back for feed-through if you really need to (like the 3D cards of yore).

I'm hoping that if USB 4.0 (or even 5.0) begins to pick up some of the functionality of thunderbolt they do it in a sane and motherboard/vendor/CPU/GPU neutral way over ONLY the PCIe bus. Use DRI PRIME or something, I don't care. The current system is a mess.

[stormcrow]

Is this for USB 4.0? Thunderbolt? Saying USB type-C is almost meaningless at this point.

One of the things I hate most about the current landscape is that somebody at intel thought it was a good idea for thunderbolt to require an extra cable and motherboard header. Supposedly these carry displayport and a bunch of (BIOS configured?) GPIO pins.

Suddenly I can only have thunderbolt if my motherboard supports the header and I buy a motherboard-specific card. At that point, why not put it on the motherboard? Why support cards at all?

It should have been PCIe-only. Put a DP input port on the back for feed-through if you really need to (like the 3D cards of yore).

I'm hoping that if USB 4.0 (or even 5.0) begins to pick up some of the functionality of thunderbolt they do it in a sane and motherboard/vendor/CPU/GPU neutral way over ONLY the PCIe bus. Use DRI PRIME or something, I don't care. The current system is a mess.

You're over thinking it. DP over USB-C means exactly that. Display port over USB with a type C connector aka USB 3.1.

From Dell's website:

What is DisplayPort™ over USB Type-C?


DisplayPort™ over USB Type-C enables the delivery of full DisplayPort A/V performance (driving monitor resolutions of 4K and beyond), SuperSpeed USB (USB 3.1) data and up to 100 watts of power with the convenience of reversible plug orientation and cable direction. DisplayPort™ is the first A/V protocol to be carried over USB Type-C.

Thunderbolt can do it too, but it's not "DisplayPort over USB Type C".

[Developer12]

What are the differences between USB 4.0 etc and thunderbolt then? Just thunderbolt's ability to carry PCIe?

[skeevy420]

This thread is a prime example of why I dislike this one cable to rule them all trend. I feel like I need a spreadsheet and flow chart to figure out which cable supports what features with different software and hardware combinations.

Even worse are cables like USB(-C) where it may or may not be capable of all the features depending on how the cable was constructed so you might have a data-only or power-only cable and you don't know which...and because there is no labeling standard you might get a sticker on the end, actual lettering/engraving (maybe useful or just a logo), or blank.

[binarybanana]

This is really needed. On my laptop I need to patch the Intel driver or else my USB-C->HDMI dongle causes some weird semi-permanent failure of the output when the monitor goes into sleep mode. Thankfully it's so easy to do on Gentoo that I completely forgot about it until yesterday, but still it would be nice if things like that just worked.

[mihau]

Even worse are cables like USB(-C) where it may or may not be capable of all the features depending on how the cable was constructed so you might have a data-only or power-only cable and you don't know which...

Not really. All USB-C cables are mandated to have at least USB 2.0 connectivity, at least 3 amp current capability and all the PD wires. You can transfer data and charge a laptop with at least 60W of power with any compliant USB-C cable.

and because there is no labeling standard you might get a sticker on the end, actual lettering/engraving (maybe useful or just a logo), or blank.

There is a standard - the USB-IF specifies it. Most manufacturers just choose not to follow it.

[skeevy420]

Not really. All USB-C cables are mandated to have at least USB 2.0 connectivity, at least 3 amp current capability and all the PD wires. You can transfer data and charge a laptop with at least 60W of power with any compliant USB-C cable.

The key words there are "at least" and "compliant". Due to your below comment we may or may not know if it is compliant or not.

There is a standard - the USB-IF specifies it. Most manufacturers just choose not to follow it.

"At least" above means the standard is variable which leads to my problem where there's so much wiggle room in the standard that they don't have to follow it to make a working cable. Then they don't have to correctly label it so you have to cross your fingers and hope the cable works. That's why even in the day of USB-C it is still good practice to use the cable that came with your device for the best results since, unfortunately, compliant for my Moto G Power isn't necessarily going to be the same as compliant for a Samsung Galaxy Something-or-Other or a Lenovo Notebook.