Nintendo Switch 2 Dock USB-C Compatibility

From lttlabs:

> The inability for most docks to support the Switch 2 may not be malicious from Nintendo. It might just be a poor or lazy implementation of the USB-C specification

From the verge [0], 2 months ago:

> When I analyze the conversation between the Nintendo Switch 2 and its dock, I can see the two devices begin speaking in Nintendo’s own flavor of “vendor defined” language early in the conversation, before they sign off on any video output. And then, seemingly before the dock confirms that it’s engaged video-out, they send over 30 proprietary “unstructured” messages to one another.

> […]

> According to Antank, which says it checked with its chip supplier, that hexadecimal string “is indeed the current key being used by Nintendo.” My other sources are less sure.

I'm pretty sure lttl's conclusion is plain wrong. It is not JUST lazy USB-C implementation, but a purposefully designed special proprietary protocol on top of USB-C

[0] https://www.theverge.com/report/695915/switch-2-usb-c-third-...

There's a lot of misunderstandings about USB PD communication, in particular Vendor Defined Messages. The LTT video kept making this mistake, and mixing in misunderstandings around messages to the eMarker chip itself (SOP'). It was a painful watch.

Vendor Defined Messages have is part of any normal PD exchange, as they're simply anything that isn't defined by the PD spec itself. You'll see VDMs when connecting any device supporting more than just dumb charging, as it's used for all sorts of things like DisplayPort, Thunderbolt, eMarker identification, etc. - stuff we'd expect ehre.

The quote from Antak refers to just a single, possibly/likely proprietary, message. This could be to ID the dock on the basis of e.g. rejecting the switch 1 dock should one cram it in, or to reject switch 1 dongles. Maybe it's Nintendo speak for "dock capabilities: cooling", with the switch having no mode for docked gaming with reduced performance without cooling.

Intentional incompatibility, yes, but it's 1 message of an unknown type within bog standard USB-PD, not a "vendor defined lanugage" or "over 30 proprietary messages".

Why reject switch 1 accessories though? Sure the video resolution will have to be limited to 1080p, but that's kinda expected and I'm sure switch 2 can do that anyway