Following the launch of Thunderbolt 4 earlier this year as part of Intel's Tiger Lake CPUs, the next piece of the TB4 hardware stack has dropped this week with the release of Intel's first stand-alone Thunderbolt 4 controller, Maple Ridge (JHL8540). Previously announced back in July as part of Thunderbolt 4's reveal, Intel this week updated their Ark database to add a product page for the Maple Ridge controller family and flag that the first part is now shipping. With the release of the discrete Thunderbolt 4 controller, it will now be possible for hardware vendors to build TB4 hosts with additional ports, or in devices not using Intel's Tiger Lake Silicon.

This late-December launch follow's Intel's previous roadmap, which had the launch of standalone controllers set to take place before the end of 2020. These included the Goshen Ridge (JHL8440) device controller – for use in docks and peripherals, and the Maple Ridge (JHL8540 and JHL8340) host controllers – for use in computers, tablets, and other client devices. Goshen Ridge went into production soon after the announcement. And with the release of Maple Ridge Intel has also kept its promise here, getting it out just prior to the end of the year.

For quite some time, Thunderbolt ports were found only on systems with Intel processors. However, last year we saw vendors such as ASRock innovate with the introduction of a Thunderbolt 3 port on the X570 Phantom Gaming-ITX/TB3, an AMD Ryzen platform motherboard. This was followed a few months back by the introduction of M1-based Macs featuring Thunderbolt 3 (backed by Apple's in-house controllers). The use of Maple Ridge will now enable motherboard vendors to create systems with Thunderbolt 4 ports that do not necessarily need to be based on Intel processors.

The JHL8540 Maple Ridge controller interfaces with the host processor using a PCIe 3.0 x4 link and also takes in two Display Port 1.4a inputs. On the downstream side, the controller enables two Thunderbolt 4 ports, which along with their native Thunderbolt (packet encapsulation) abilities can also be used as straight-up USB4 ports, or as DisplayPorts via USB-C's DP alt mode.

The PCIe switch and, in general, the PCIe support in Maple Ridge has been updated to work with many optional features, keeping security in mind and the rich variety of PCIe devices coming into the market. For example, Maple Ridge includes PCIe peer-to-peer support which allows two PCIe devices connected to the two Thunderbolt 4 ports to exchange data with each other without having to make it travel upstream to the host RAM. From a security viewpoint, Access Control Services (ACS) is also supported to provide isolation between different sets of PCIe devices and make them always go through the IOMMU. Precision Time Measurement (PTM) is also a supported feature, allowing different downstream PCIe devices to accurately synchronize with each other and the host system.

It must be noted that Thunderbolt 4 brings more guaranteed bandwidth to end-users. With Thunderbolt 3, device vendors could skimp on the connection of the controller to the host processor – using only a PCIe 3.0 x2 upstream link instead of PCIe 3.0 x4, but still obtain Thunderbolt 3 certification. This reduced the minimum available PCIe data bandwidth to just 16 Gbps. With Thunderbolt 4, that is no longer possible. Vendors are mandated to use a full PCIe 3.0 x4 link if they desire Thunderbolt 4 certification. Thunderbolt 3's bandwidth sharing mechanism between video and data also put in some dampeners – even in the absence of tunneling DisplayPort streams, 18 Gbps of bandwidth was always reserved for video traffic, and only 22 Gbps available for actual data transfer. Thunderbolt 4 apparently fixes that with up to 32 Gbps of data traffic (full PCIe 3.0 x4 bandwidth) available, allowing devices such as Thunderbolt 4 SSDs to provide 3GBps+ speeds.

Intel has not published official pricing of the new Maple Ridge controller, however Mouser Electornics is listing the controllers for as cheap as $11.34 in bulk quantities. As for the availability of devices featuring the JHL8540, I suspect we're going to see them sooner than later. Intel's next-generation desktop platform, Rocket Lake-S, is not expected to have built-in support for Thunderbolt 4, as this feature was noticeably absent from Intel's Rocket Lake reveal back in October. So adding Thunderbolt 4 to Rocket Lake-S will likely require using Maple Ridge.

This would be consistent with other documentation from Intel, such as the Intel 500 series chipset guidelines, which apparently point to instructions to use a discrete USB4-compliant Intel Thunderbolt 4 controller connecting to four PCIe 3.0 lanes from the chipset for USB4/Thunderbolt 4 support. To that end, we expect that the development of actual hardware by Intel’s partners using the Maple Ridge controller should be well under way by now.

Source: Intel

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  • repoman27 - Thursday, December 24, 2020 - link

    That would be the Goshen Ridge JHL8440 in the OWC Thunderbolt Hub / Dock. The folks that put in for the initial pre-order are just starting to receive units now, according to reports over at MacRumors.
  • Deicidium369 - Sunday, December 27, 2020 - link

    More looking at Sonnet's TB3 to SFP+ for the upcoming NUC11 Pro models - been testing on my Dell XPS 13 with the 1165G7 - and full 10Gb/s line speed is easily achieved and sustained - and I can finally use the fiber I ran throughout - and will be able to use the full 10Gb/s port speed on the Cisco switches rather than burning a port with a 2.5Gb/s copper connection.
  • KimGitz - Saturday, December 26, 2020 - link

    I really love and appreciate what Intel has done with Thunderbolt from the initial development to the latest Thunderbolt 4. With Thunderbolt 4 it is clear to see Intel's commitment to making sure Thunderbolt is really the best USB-C implementation.

    Thunderbolt 4 is really great on the device side with the Goshen Ridge JHL8440 Thunderbolt 4 controller because it combines the best feature from USB, the new Multi-Port Accessory Architecture with the Daisy Chain Accessory Architecture in one product. Also having full bandwidth when a Thunderbolt 4 devices is connected to a USB4 40 host with Thunderbolt 3 compatibility which gives a 360 degrees full circle relationship.

    My ideal Thunderbolt 4 dock includes 4x Thunderbolt 4/USB4 USB-C ports (1UP+3DWN), 2 Display (HDMI 2.0 and/or DisplayPort 1.4), 4x USB 3.2 USB-A with quick charge, 1x 10GbE with AVB support.

    Moving forward Intel will likely have Thunderbolt integrated to desktop CPUs just as they did with the mobile CPUs like Ice Lake and Tiger Lake. However it will be great to see AMD motherboards with a Maple Ridge Controller to add Thunderbolt 4 and USB4 support. It will be great to see ARM support thunderbolt on something like the Surface Pro X. It will be even better if Microsoft ditched their surface connect and just used Thunderbolt 4 on their next Surface Computers.

    I can't wait for Intel to move Thunderbolt to PCIe 4.0 and DisplayPort 2.0; PCIe 3.0 and DisplayPort 1.4 are already bottlenecks.
  • Deicidium369 - Sunday, December 27, 2020 - link

    Rocket Lake will use something similar to this Maple Ridge - not integrated on the CPU. One can assume that Alder Lake will have it integrated in
  • KimGitz - Monday, December 28, 2020 - link

    Many 500 series Intel motherboards will feature the Maple Ridge. Outside Apple's M1 Thunderbolt integration, there have been no other 3rd party Thunderbolt controllers announced. Gigabyte have historically led the way for Intel motherboards with Thunderbolt support. AsRock on the other hand took the lead with support for Thunderbolt on their AMD motherboards.
    Alder Lake will most probably be the 1st generation to feature Thunderbolt integrated to both Desktop and Laptop CPUs. I'm just hoping it will also means upgrading to PCIe 4.0.
  • lilkwarrior - Saturday, December 26, 2020 - link

    Good; hopefully someone makes a Thunderbolt 4 KVM Switch w/ this.
  • KimGitz - Monday, December 28, 2020 - link

    With Thunderbolt 4 we get wake up PC feature using a connected mouse or keyboard on a hub/dock, which is a great potential feature for a KVM Switch.
  • WaltC - Tuesday, December 29, 2020 - link

    Will this be the Thunderbolt version that fixes all the bugs of the last revision of Thunderbolt?
  • KimGitz - Thursday, December 31, 2020 - link

    We can expect every Thunderbolt 4 Host to act the same regardless of platform. We can expect Thunderbolt 4 devices to have better cross platform performance. We can expect the Thunderbolt 4 cable to work regardless of protocol or platform. It really is unfortunate that the first ARM Based Apple M1 Silicon doesn't get Thunderbolt 4 certification mainly due to only supporting one external display and maybe no eGPU support.

    The is only one thing Thunderbolt 4 doesn't fix is BANDWIDTH.
    Thunderbolt 4 is still PCIe 3.0 x4 and 2x DisplayPort 1.4, which is already a bottleneck with PCIe 4.0 SSDs and 8K HDR 60Hz Display Panels.

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