4 ms·

One thing to note is that the JHL8040R is a TB retimer not a controller. The difference is a controller “speaks” the TB protocol and exposes USB, PCIe, and DP s

by osy 6y ago

One thing to note is that the JHL8040R is a TB retimer not a controller. The difference is a controller “speaks” the TB protocol and exposes USB, PCIe, and DP signals to the (typically) PCH and/or Intel CPU. They’re typically 10-20W and, from personal experience, absolute shit to work with (buggy firmware). A retimer is a < 1W part that just strengthens the TB signal coming from the outside world and cleans it up so the controller (integrated in the M1 here presumably) does not have to deal with a weak or noisy signal. Important to note that Intel plans to integrate a TB4 controller in their future (mobile?) processors but seems like Apple beat them to it. Also it’s unclear if M1’s integrated TB controller is TB3 or TB4 (you can have a TB4 retimer drive only TB3 signals).

realityking 6y ago
According to Apple's tech specs is Thunderbolt 3: https://www.apple.com/mac-mini/specs/ https://www.apple.com/mac-mini/specs/ Aside: I''m sure I had read before that the M1 Macs come with USB4 and Thunderbolt 3. However the tech specs say it's USB 3.1 Gen 2 and Thunderbolt 3.
- jeffbee 6y ago
  The marketing site clearly says USB4. """With two screaming-fast Thunderbolt / USB 4 ports, two USB-A ports, HDMI 2.0, Wi-Fi 6, and Gigabit Ethernet, Mac mini is up for anything and everything."""
- coder543 6y ago
  The tech specs page you linked says both things: "USB 4 ports with support for [...]" "USB 3.1 Gen 2" It's rather confusing. Is USB 4 just another name for USB 3.1 Gen 2 with Thunderbolt 3 support? I wouldn't put it past the USB IF to come up with something like that, but I don't think that's correct here.
  - vvhn 6y ago
    USB4 is essentially a branding strategy around the USB C connector which with tunneling various standards (USB 3.2 , thunderbolt ) and speeds. Some are required and some are optional to get branded as USB4.
    - jsmith45 6y ago
      One could alternatively describe it more as a rebranding of thunderbolt multiplexing layer. For those unfamiliar: USB4 does not specify how to interface with specific non-host devices like USB 3 and older did. Instead it is a multi-protocol tunneling (think multiplexing with routing) system, that allows tunneling USB3.2, Display Port, and optionally PCI-E (i.e. what thunderbolt is known for). It also specifies a requirement of support for different alternate modes, like display-port alternate mode (non-tunneled), and optionally thunderbolt 3 alternate mode. (Thunderbolt 3 runs at a different rate than USB4, among a small list of other differences, not counting the additional features specified in USB4). Hubs are required to support the otherwise optional thunderbolt 3 alternate mode and USB4 tunneled PCI-E, thereby making every USB4 hub a valid Thunderbolt hub, both for classic thunderbolt (TB3), and for USB4-based thunderbolt (i.e. using PCI-E tunneling in USB4, which I assume part of the updates made in TB4) Hubs will also support plain USB 3.X from a host, since USB4 is just a negotiated alternate mode over USB3. Thus USB3 can be used unencapsulated if only the hub supports USB4; Fully encapsulated if Host, hub, and device all support USB4; or partially encapsulated, like if the host and hub support USB4, but one of the downstream devices only supports USB3. The hub becomes responsible for encapsulating/unencapulating the tunneled USB3. In a similar way, a hub can support connecting a classic thunderbolt (TB3) device to a hypothetical host that only supports USB4 PCI-E encapsulation. The upstream port and downstream ports are independent, so one can use the TB3 data rate while the other can use USB4, and the hubs are required to pass the PCI-E data through a PCI-E switch, so everything just works. (Especially since talking TB3 is deliberately nearly the same as talking USB4, other than link speed). Obviously, USB2 is of course supported as well, in parallel to all other modes since it has separate data lines. But USB4 is not all perfect. For example every USB4 port on a host must support display-port output. That is not really a huge problem on say a laptop, but it is a pain on enthusiast PC building, since it means motherboards will need a display-port passthrough socket in order to support that requirement. And undoubtedly there are or will be many non-compliant devices out there that break the whole intended it-just-works approach.
- m_eiman 6y ago
  That page says: "Two Thunderbolt / USB 4 ports with support for: * DisplayPort * Thunderbolt 3 (up to 40Gb/s) * USB 3.1 Gen 2 (up to 10Gb/s) * Thunderbolt 2, HDMI, DVI, and VGA supported using adapters (sold separately)" The wording isn't terribly clear, but given this snippet from Wikipedia's USB4 page: "The USB4 specification is based on the Thunderbolt 3 protocol specification.[2] Support of interoperability with Thunderbolt 3 products is optional for USB4 hosts and USB4 peripheral devices and required for USB4 hubs on its downward facing ports and for USB4-based docks on its downward and upward facing ports." I'd say it's a USB4 port that is also compatible with TB3 and USB 3.1 gen 2.
pier25 6y ago
> They’re typically 10-20W Ah so that's why whenever I plug anything into a TB port the CPU temps go up by 10ºC. This has happened on all my macs since TB1.
ksec 6y ago
> Also it’s unclear if M1’s integrated TB controller is TB3 or TB4 AFAIK TB4's spec was never opened up and only TB3 was donated to USB Forum. Not to mention the Spec of TB4 was only finalised and released sometime this year so I seriously doubt M1 would have TB4. And It is pretty clear Apple implemented USB4, which is basically USB 3.2 with USB-C being Mandatory with optional TB3 compatibility.
dwaite 6y ago
Perhaps you could explain the difference between TB3 and 4 - my understanding was that TB4 was a branding/certification mark now by intel on top of USB4's integration of TB3 tech into the specification. It requires certain architectural features outside of conformance, such as memory protections. But to hear your post, it sounds like there is a difference between a TB3 and TB4 retimer. Are there other additions to TB4?
- osy 6y ago
  https://newsroom.intel.com/wp-content/uploads/sites/11/2020/07/thunderbolt4-comparison-chart.jpg https://newsroom.intel.com/wp-content/uploads/sites/11/2020/...

by osy 6y ago

realityking 6y ago

According to Apple's tech specs is Thunderbolt 3: https://www.apple.com/mac-mini/specs/ https://www.apple.com/mac-mini/specs/ Aside: I''m sure I had read before that the M1 Macs come with USB4 and Thunderbolt 3. However the tech specs say it's USB 3.1 Gen 2 and Thunderbolt 3.

jeffbee 6y ago
The marketing site clearly says USB4. """With two screaming-fast Thunderbolt / USB 4 ports, two USB-A ports, HDMI 2.0, Wi-Fi 6, and Gigabit Ethernet, Mac mini is up for anything and everything."""
coder543 6y ago
The tech specs page you linked says both things: "USB 4 ports with support for [...]" "USB 3.1 Gen 2" It's rather confusing. Is USB 4 just another name for USB 3.1 Gen 2 with Thunderbolt 3 support? I wouldn't put it past the USB IF to come up with something like that, but I don't think that's correct here.
- vvhn 6y ago
  USB4 is essentially a branding strategy around the USB C connector which with tunneling various standards (USB 3.2 , thunderbolt ) and speeds. Some are required and some are optional to get branded as USB4.
  - jsmith45 6y ago
    One could alternatively describe it more as a rebranding of thunderbolt multiplexing layer. For those unfamiliar: USB4 does not specify how to interface with specific non-host devices like USB 3 and older did. Instead it is a multi-protocol tunneling (think multiplexing with routing) system, that allows tunneling USB3.2, Display Port, and optionally PCI-E (i.e. what thunderbolt is known for). It also specifies a requirement of support for different alternate modes, like display-port alternate mode (non-tunneled), and optionally thunderbolt 3 alternate mode. (Thunderbolt 3 runs at a different rate than USB4, among a small list of other differences, not counting the additional features specified in USB4). Hubs are required to support the otherwise optional thunderbolt 3 alternate mode and USB4 tunneled PCI-E, thereby making every USB4 hub a valid Thunderbolt hub, both for classic thunderbolt (TB3), and for USB4-based thunderbolt (i.e. using PCI-E tunneling in USB4, which I assume part of the updates made in TB4) Hubs will also support plain USB 3.X from a host, since USB4 is just a negotiated alternate mode over USB3. Thus USB3 can be used unencapsulated if only the hub supports USB4; Fully encapsulated if Host, hub, and device all support USB4; or partially encapsulated, like if the host and hub support USB4, but one of the downstream devices only supports USB3. The hub becomes responsible for encapsulating/unencapulating the tunneled USB3. In a similar way, a hub can support connecting a classic thunderbolt (TB3) device to a hypothetical host that only supports USB4 PCI-E encapsulation. The upstream port and downstream ports are independent, so one can use the TB3 data rate while the other can use USB4, and the hubs are required to pass the PCI-E data through a PCI-E switch, so everything just works. (Especially since talking TB3 is deliberately nearly the same as talking USB4, other than link speed). Obviously, USB2 is of course supported as well, in parallel to all other modes since it has separate data lines. But USB4 is not all perfect. For example every USB4 port on a host must support display-port output. That is not really a huge problem on say a laptop, but it is a pain on enthusiast PC building, since it means motherboards will need a display-port passthrough socket in order to support that requirement. And undoubtedly there are or will be many non-compliant devices out there that break the whole intended it-just-works approach.
m_eiman 6y ago
That page says: "Two Thunderbolt / USB 4 ports with support for: * DisplayPort * Thunderbolt 3 (up to 40Gb/s) * USB 3.1 Gen 2 (up to 10Gb/s) * Thunderbolt 2, HDMI, DVI, and VGA supported using adapters (sold separately)" The wording isn't terribly clear, but given this snippet from Wikipedia's USB4 page: "The USB4 specification is based on the Thunderbolt 3 protocol specification.[2] Support of interoperability with Thunderbolt 3 products is optional for USB4 hosts and USB4 peripheral devices and required for USB4 hubs on its downward facing ports and for USB4-based docks on its downward and upward facing ports." I'd say it's a USB4 port that is also compatible with TB3 and USB 3.1 gen 2.

pier25 6y ago

> They’re typically 10-20W Ah so that's why whenever I plug anything into a TB port the CPU temps go up by 10ºC. This has happened on all my macs since TB1.

ksec 6y ago

> Also it’s unclear if M1’s integrated TB controller is TB3 or TB4 AFAIK TB4's spec was never opened up and only TB3 was donated to USB Forum. Not to mention the Spec of TB4 was only finalised and released sometime this year so I seriously doubt M1 would have TB4. And It is pretty clear Apple implemented USB4, which is basically USB 3.2 with USB-C being Mandatory with optional TB3 compatibility.

dwaite 6y ago

Perhaps you could explain the difference between TB3 and 4 - my understanding was that TB4 was a branding/certification mark now by intel on top of USB4's integration of TB3 tech into the specification. It requires certain architectural features outside of conformance, such as memory protections. But to hear your post, it sounds like there is a difference between a TB3 and TB4 retimer. Are there other additions to TB4?

osy 6y ago
https://newsroom.intel.com/wp-content/uploads/sites/11/2020/07/thunderbolt4-comparison-chart.jpg https://newsroom.intel.com/wp-content/uploads/sites/11/2020/...