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  • #41
    Originally posted by anth View Post

    I've always thought the claims of extra bandwidth from TB compared with USB were a bit misleading. They are correct but with a caveat.

    PCIe over Thunderbolt 3 has the same maximum 20Gb/s bandwidth per direction as the USB 3.x protocol. The difference is USB (3.2 Gen 2x2) uses the two SuperSpeed+ lanes in one direction and the other two lanes in the other direction, but only does one direction at a time rather than both at once. TB also uses two lanes in each direction but can do both at once, though it is limited to a length of 0.5m or an active cable.
    orrect but with a caveat.

    PCIe over Thunderbolt 3 has the same maximum 20Gb/s bandwidth per direction as the USB 3.x protocol. The difference is USB (3.2 Gen 2x2) uses the two SuperSpeed+ lanes in one direction and the other two lanes in the other direction, but only does one direction at a time rather than both at once. TB also uses two lanes in each direction but can do both at once, though it is limited to a length of 0.5m or an active cable.

    DisplayPort 1.2 to 1.4 can use the HBR3 transmission mode from that standard as a USB-C alternate mode, with 1, 2, or all 4 SuperSpeed+ lanes, for a maximum bandwidth in one direction of 32.4Gb/s.

    I've not got to grips with USB 4 yet.
    DisplayPort 1.2 to 1.4 can use the HBR3 transmission mode from that standard as a USB-C alternate mode, with 1, 2, or all 4 SuperSpeed+ lanes, for a maximum bandwidth in one direction of 32.4Gb/s.

    I've not got to grips with USB 4 yet.
    At Physical Layer , Thunderbolt3 has the same speed Limitation as USB3.2 over USB-C..
    What turns it faster is the Paralel behavior in full duplex.. I agree
    Also,
    USB 3.2 on the 2 new modes SuperSpeed+, uses a 128b/132b encoding, which improves the transfers, but maybe give him a bit of latency, compared with the more conservative 8b/10b..

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    • #42
      Originally posted by brent View Post
      Security hasn't been an issue with Thunderbolt for many years now. I don't get it why uneducated people still bring this up all the time. UEFI system firmwares (those that I know) have configurable Thunderbolt policies and OS support with opt-in policies for new devices is easy to enable (or even default), too. Of course IOMMU with proper configuration is a plus, but if security policies keep unwanted Thunderbolt devices separated from the host on the PCIe level, you don't need it.
      Without proper IOMMU handling, thunderbolt can quickly turn into a real nightmare. I mean, if I tried to count how many external USB devices I have in my home, it would certainly be more than 30. Imagine what would happen if all those 30 devices were using USB 4.0. I would have to put each one of them separately on some kind of idiotic access list, and even that doesn't guarrantee me security since another device can fake the ID of an already connected device.

      Therefore, IOMMU is a must.

      Of course, you can say that I can just disable thunderbolt functionality, but then, why do I need USB 4.0 at all? What if I have a laptop dock/GPU which needs it? Does every UEFI have this setting? And, I am supposed to remember to toggle this setting in the UEFI every time I carry the laptop outside the house? That is rediculous.

      What "configurable thunderbolt policies" in UEFI are you takling about? If it consists of "1-enable, 2-disable, 3-fuck off", than it is obviously insufficient.


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      • #43
        Originally posted by xfcemint View Post
        What "configurable thunderbolt policies" in UEFI are you takling about? If it consists of "1-enable, 2-disable, 3-fuck off", than it is obviously insufficient.
        By now you should have realized you suffer from a serious lack of information in regards to Thunderbolt. Why don't you go and fix that, instead of bothering other people with your stupidity?

        The default security mode for Thunderbolt is "secure". The controller in the host device does not automatically tunnel any PCIe lanes when you attach a PCIe-capable device to the bus. The user has to authorize the device to make that happen, and the operating system remembers the device so it can re-authorize it automatically in the future. This is also true for all current UEFI implementations I've worked with. All Thunderbolt-capable systems I've seen in the last four years had safe defaults both in the UEFI settings and the operating systems.

        Here's a blog post from someone who actually tried to hack a stock system via Thunderbolt back in 2016 and failed:

        http://blog.frizk.net/2016/10/dma-at...usb-c-and.html

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        • #44
          Originally posted by Marc Driftmeyer View Post

          Yes it does and for those in the creative arts that deal with Soundtracks, Music creation, Film Production, Animation, etc etc., you bet your ass we want PCIe access. We want as much bandwidth as possible.

          See page 66 of the spec and read from there.

          Anyone incapable of securing their work environment is on them. Sorry, but knee capping for the sake of `security' by compromising bandwidth is absurd.
          Isn't that a false dilemma? I mean, nobody's saying external PCIe is necessarily a bad thing? Would it really be so horrible if you had USB not doing PCIe and things like OCuLink that did? Ideally, I think, we would have a few different types of connectors, a user-level connector, an OS-level connector and a hardware-level connector. I mean, PCIe is much more dangerous than USB and USB is much more dangerous than it ought to be for simple things like headphones or simple storage on your keyring.

          In my opinion, separating things by level of danger, is not a stupid idea.

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          • #45
            Originally posted by johannesburgel View Post
            By now you should have realized you suffer from a serious lack of information in regards to Thunderbolt.
            I do, that's why I asked the question.

            Originally posted by johannesburgel View Post
            Why don't you go and fix that, instead of bothering other people with your stupidity?
            Why do you bother to post your stupidities?

            Originally posted by johannesburgel View Post
            The default security mode for Thunderbolt is "secure". The controller in the host device does not automatically tunnel any PCIe lanes when you attach a PCIe-capable device to the bus. The user has to authorize the device to make that happen, and the operating system remembers the device so it can re-authorize it automatically in the future. This is also true for all current UEFI implementations I've worked with. All Thunderbolt-capable systems I've seen in the last four years had safe defaults both in the UEFI settings and the operating systems.
            That doesn't answer at least the following security concerns:

            1) Can an an attached device sucessfully fake another device ID?
            2) After you have authorized a device ID, is it possible for the device to access unauthorised areas in the memory?

            Originally posted by johannesburgel View Post
            Here's a blog post from someone who actually tried to hack a stock system via Thunderbolt back in 2016 and failed:
            http://blog.frizk.net/2016/10/dma-at...usb-c-and.html
            Thanks, that was an interesting read. However, the conclusion is far from "all OK". It says (quoted):

            "The default Thunderbolt security settings are secure - unless you approve a Thunderbolt to PCI Express adapter like the Sonnet Echo ExpressCard."

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            • #46
              Originally posted by L_A_G View Post
              I suspect that the idea is to let device makers include both older and USB 4.0+ ports for devices and then eventually just let consumers use cheap "legacy USB hubs" to support their legacy devices. There's only so much legacy cruft that you can have in your standard before it becomes unwieldy and unmanageable.
              Makes sense, that probably is their intent. But it kind of takes the "universal" out of universal serial bus. These devices only work in these USB ports, but these other devices, you have to plug them into those other USB ports over there. Whatever, if there's one thing the USB people are good at, it's creating consumer confusion.

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              • #47
                Originally posted by torsionbar28 View Post
                Makes sense, that probably is their intent. But it kind of takes the "universal" out of universal serial bus. These devices only work in these USB ports, but these other devices, you have to plug them into those other USB ports over there. Whatever, if there's one thing the USB people are good at, it's creating consumer confusion.
                Considering this is the first time the standard is dropping any backwards compatibility in the 23 years the standard has existed I doubt this is going to be something that happens regularly. It's not like you've been able to plug in original SCSI peripherals (the standard being finalized in 1986) without any kind of adapters into modern devices since the early 2000s and you rarely saw people kick up a fuss about that back then.
                "Why should I want to make anything up? Life's bad enough as it is without wanting to invent any more of it."

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                • #48
                  The faster they iterate on new versions of protocols & connectors, the less "Universal" the "Universal Serial Bus" becomes.

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                  • #49
                    It must be becoming increasingly complex and expensive to implement the latest USB standards on modern computers.

                    Peripherals can still be kept relatively simple, as they only need to implement the tiny subset of USB that they use.

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                    • #50
                      Originally posted by cybertraveler View Post
                      It must be becoming increasingly complex and expensive to implement the latest USB standards on modern computers.

                      Peripherals can still be kept relatively simple, as they only need to implement the tiny subset of USB that they use.
                      You would be correct. With the new features baked into USB-C and Thunderbolt, many board makers have simply passed on implementing either one, because the required hardware and design changes to go beyond the physical connection itself adds significant cost to board designs. That's why adoption of both interfaces in hardware beyond storage devices has been very small in comparison to USB 3.0, which is as easy to use as it's predecessor.

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