I read from the USB4 spec that PCIe signal now can be tunneled over USB4 connection. But it is an optional feature. Is it supported on the 11th gen or 12th gen Intel Framework laptop?
It is. eGPUs and eNVMes work fine on the Framework.
@Shiroudan Aren’t those usually done via Thunderbolt?
Thunderbolt uses PCIe tunneling to achieve compatability with these!
Yes the framework laptop has unofficial Thunderbolt 4 support. I’m using my laptop with an EGPU box right now!
I understand thunderbolt 3/4 is supported (unofficially) as alt mode via the USB type C interface. Thanks for the confirmation that it does work.
I am curious however about the USB4 side of thing. The USB4 specification includes its own kind of PCIe tunneling so you can get PCIe connectivity directly out of USB4 without Thunderbolt (as long as the USB4 controllers at the host and device support it).
ASMedia has demoed its upcoming USB4 device controller ASM2464PD that supports such optional feature:
P.S. The IC below the silver heatsink is a USB4 controller.
As this feature of USB4 is deemed optional in the spec, I am wondering if any of the four Framework Laptop’s Type C ports supports this feature.
Please correct me if im wrong on this.
But to my knowledge USB4 is kind of “based on” thunderbolt, with the only difference being that USB4 has lower minimum specifications and parts of the featureset is optional.
Thunderbolt on the other hand requires all the bells and whistles.
Frameworks USB-C ports are all Thunderbolt compatible, meaning they have all the bells and whistles, but are not officially certified by intel.
@Simon_F I thought USB4 was a less stringent Thunderbolt 3 too at first glance. But from what I have read, it seems it is the all-new USB4 packet-based data transmission protocol (the “USB4 Fabric”) that is derived from Thunderbolt 3 but crucially they are not the same. That’s why the optional compatibility with Thunderbolt 3 is considered “interoperability” in the specification. Moreover Thunderbolt 3 is still run in alt mode (not tunneled via the “USB4 Fabric”).
FYI this is how PCIe tunneling is depicted in the USB4 spec. It does resemble how Thunderbolt tunnels things.
Interesting, seems like i have some more digging to do
As a side note the Framework USB-C ports say they support USB4
@Shiroudan Yes but sadly the PCIe tunneling feature is optional by the spec. Also the USB4 feature set supported by the Framework laptop is pretty vague. (Frankly most on the market now are equally if not more vague…) Hence I started this thread.
I suspect only the required feature set (which includes only Gen2x2 20Gbps and DisplayPort Alt Mode) is supported at the moment.