USB Type-C Improvements On The Way To The Linux 4.17 Kernel

[phoronix]

Phoronix: USB Type-C Improvements On The Way To The Linux 4.17 Kernel

The Linux 4.17 kernel is bringing further improvements to USB Type-C support...

http://www.phoronix.com/scan.php?page=news_item&px=USB-Type-C-Linux-4.17

[samdraz]

hope that is stable enough to move it out of staging

[edwaleni]

Does anyone know if the current kernel can exploit the full USB 3.2 spec with the correct hardware?

• USB 3.2 Gen 2x2 - SuperSpeed+, new 20 Gbit/s (2500 MB/s) data rate over 2 lanes using 128b/132b encoding.

This spec came out in September 2017. With regards to upgrade options, there were only 2 PCIe 3.1 boards and it was only a subset of the Gen 1 specification they permitted.

Making matters worse is Intel and some of the laptop makers. Their chipsets support 3.1/Thunderbolt, but it is not wired for it on the planar. Some makers were saying they did it to maintain competitive battery life specs. Some were complaining that 3.1 required power at the A and C jack. Worse yet, some makers are installing USB-C jacks, but they only work at USB3 data rates.

[Happy Heyoka]

Worse yet, some makers are installing USB-C jacks, but they only work at USB3 data rates.

don't know the answer to your USB 3.2 question but it's a pain that the connector standard (USB-C) doesn't imply any link standard (ie: can happily be USB 2.0 data rate afaik); that's not confusing at all

[edwaleni]

[Sniperfox47]

don't know the answer to your USB 3.2 question but it's a pain that the connector standard (USB-C) doesn't imply any link standard (ie: can happily be USB 2.0 data rate afaik); that's not confusing at all

You mean kinda like how Type-A can be 1.0, 1.1, 2.0, 3.0, 3.1gen1 or 3.1gen2? :P

Or do you mean that its not color coded? Because Asus gaming laptops definitely have both 3.0 and 2.0 type-A ports that are red coloured. :P

[edwaleni]

You mean kinda like how Type-A can be 1.0, 1.1, 2.0, 3.0, 3.1gen1 or 3.1gen2? :P

Or do you mean that its not color coded? Because Asus gaming laptops definitely have both 3.0 and 2.0 type-A ports that are red coloured. :P

All, if not most Type A ports are color coded. Blue has been the USB3.x method. Type C have not been color coded between 3.x, 3.1 Gen1 or Gen2. I think i have seen 1 Type C cable that actually said "3.1" on it.

The "sin" has been laptop makers wiring up a Type C port to a USB 3.x/Gen1 controller which was never ratified by the USB standards board. People will think they will get Gen2/10Gbps rates, when Gen 1 (5Gbps) is the real rate.

I am going through the approved adapter list at USB.ORG to see if they have any certified for "full" Gen1/2 or 3.2 use. For those who ask, "full" USB 3.1 should be able to pass video or GbE via virtual interfaces in the OS. Most of the adapters outside of Apple can not do this without a dongle of some sort.

Then see which ones have explicit Linux support.

[PuckPoltergeist]

USB 1.0: 1996
Thunderbolt 1: 2011

[Sniperfox47]

All, if not most Type A ports are color coded. Blue has been the USB3.x method. Type C have not been color coded between 3.x, 3.1 Gen1 or Gen2. I think i have seen 1 Type C cable that actually said "3.1" on it.

The "sin" has been laptop makers wiring up a Type C port to a USB 3.x/Gen1 controller which was never ratified by the USB standards board. People will think they will get Gen2/10Gbps rates, when Gen 1 (5Gbps) is the real rate.

I am going through the approved adapter list at USB.ORG to see if they have any certified for "full" Gen1/2 or 3.2 use. For those who ask, "full" USB 3.1 should be able to pass video or GbE via virtual interfaces in the OS. Most of the adapters outside of Apple can not do this without a dongle of some sort.

Then see which ones have explicit Linux support.

You have a massive misunderstanding of the USB Type-C spec. Alt-modes including DisplayPort, GbE, Power Delivery, and others are an *optional* part of the spec, for both controllers and ports themselves.

There's specifically USB-C muxes and multiplexers designed to combine alt-modes and USB data lines on one Type-C port, and this is totally allowed under the USB spec.

The specs are fully available for free here if you want to read through them: http://www.usb.org/developers/docs/

Under the Type-C spec it even explocitly calls out that Type-C is simply a connector spec, which is decoupled from any specific USB data spec, and those in turn are decoupled from any Alt-mode.

None of 3.1gen1, 3.1gen2, or 3.2 imply DisplayPort Alt-mode, or any other Alt-mode.

[edwaleni]

You have a massive misunderstanding of the USB Type-C spec. Alt-modes including DisplayPort, GbE, Power Delivery, and others are an *optional* part of the spec, for both controllers and ports themselves.

There's specifically USB-C muxes and multiplexers designed to combine alt-modes and USB data lines on one Type-C port, and this is totally allowed under the USB spec.

The specs are fully available for free here if you want to read through them: http://www.usb.org/developers/docs/

Under the Type-C spec it even explocitly calls out that Type-C is simply a connector spec, which is decoupled from any specific USB data spec, and those in turn are decoupled from any Alt-mode.

None of 3.1gen1, 3.1gen2, or 3.2 imply DisplayPort Alt-mode, or any other Alt-mode.

"Massive?". I am familiar with alt-modes. and muxing onto the Type C port. That is why I said less than "full" specification.

Why show a Type C is only under Gen1 or 2 when the USB spec says otherwise? Hence the graphic above.

The point beyond my original Linux support request is that while the standards are published, in the market is confusion.