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M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

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Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#161

Post by harha »

post_break wrote: post #133
harha wrote: post #114

Earlier quoted context omitted.

Not sure this is fair to the consumer. Apple was advertising usb-c as one port to rule then all. When the device has two of these ports, why should the user expect not to connect two displays? Especially since this restriction didn’t apply to the previous models that looked exactly the same and are now advertised as less powerful. It would be natural to not explicitly look for how many displays it can handle.

Back in 2011 you could use a second iMac is a monitor in target display mode, that went away, why should the user expect not to be able to use target display mode for every iMac? Things change unfortunately and the single display restriction of M1 was advertised heavily online and can be a pain point but it's listed online as a spec.

Good point, though I’d argue more people use two screens on a MacBook than an iMac as a screen, since it already provides a computer.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#162

Post by colejohnson66 »

faller wrote: post #156
colejohnson66 wrote: post #152

Earlier quoted context omitted.

You keep dancing around my arguments. The issue isn't that things have changed; it's that they've changed in a way that makes things confusing for consumers. Go ask a random person on the street which is better: "USB 3.2 Gen 1 or USB 3.0?" I guarantee you'll find people thinking "USB 3.2 Gen 1" is better because it's a bigger number. But despite that, they're the exact same thing : 5 Gb/sec ("SuperSpeed").

> You keep dancing around my arguments. No, not really. Feel free to point out exactly which argument you feel was ignored. > The issue isn't that things have changed; it's that they've changed in a way that makes things confusing for consumers. That seems to be the source of your confusion: nothing has changed. Each USB spec is backwards compatible and specifies the same data transfer modes. And there is no confusio…

> Feel free to point out exactly which argument you feel was ignored.

The retroactive renaming of speed+versions. I'm not talking about the Mac.

> If you pick up a USB3.1 device you know beforehand it won't support SuperSpeed+ 2x or 4x.

My whole argument is that this confusion wouldn't be an issue if the USB Consortium had reserved USB 3.1 for 10 Gb/sec speeds exclusively. In other words, this:

    3.0: 5 Gb/s  "SuperSpeed"
    3.1: 10 Gb/s "SuperSpeed+"
    3.2: 20 Gb/s "SuperSpeed++"
That, and that alone (with none of the "Gen" nonsense) would avoid confusion. Then, if I pick up a USB 3.1 device, I would know it's 10 Gb/sec "SuperSpeed+" without having to use a stupid "generation" number. But no, the USB Consortium decided to deprecate 3.0 and 3.1 because all new devices are "3.2 Gen whatever". That's confusion.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#163

Post by Diggsey »

faller wrote: post #123
grishka wrote: post #48

Earlier quoted context omitted.

> USB 3.1 Gen 1 is the straight rebranding of USB 3.0 Why? To solve what exactly? In a sane world, it'd be major.minor, with nothing appended at the end. Allowing marketers to take over everything was such a terrible mistake. At this point I myself just don't differentiate USB versions beyond 3.0. 2.0 is the slow one, 3.0 is the fast one, anything newer is "so fast I won't ever saturate this much bandwidth anyway". T…

> Why? To solve what exactly? In a sane world, it'd be major.minor, with nothing appended at the end. It's always important to get acquainted with a topic before succumbing to the desire to mindlessly criticize in ignorance. A quick search in Wikipedia shows that USB 3.1 specifies a brand new transfer rate, dubbed SuperSpeed+ transfer mode , " (...)which can transfer data at up to 10 Gbit/s over the existing USB3-typ…

The problem is that the version of the standard is conflated with the version of the port. Here is a better system:

1) The standard has a version number. I would have suggested semver, except that USB will always be backwards compatible within the same physical port, so there's no need for separate major/minor versions. We can just use an incrementing number 1,2,3 etc.

2) The standard gives each physical port layout a name, eg. A, B, C. Port layouts can be added/removed in new versions of the standard.

3) The standard specifies and names various transfer rates, eg. T1, T2, etc with new names being added in new versions of the standard. (eg. version 1 defines speed T1, version 2 defines speeds T1, T2. etc.)

4) Manufacturers are not allowed to use the version of the USB specification in their marketing material at all. A port is not "USB 3.1", it's "USB C T2".

The version of the spec only serves to confuse customers because the whole point is that versions are backwards compatible. The only thing the customer cares about is the physical port layout and what features/transfer rate are supported over that port.

So the marketing names would be:

USB A T1, USB A T2

USB C T1, USB C T2, USB C T3

As a customer, I can easily see that I can't plug a "USB A T1" into a "USB C T1" because they are different physical ports. I can also see that "USB C T2" is faster than "USB C T1".

Admittedly thing are slightly more complicated because the transfer rate is not the only "feature", we also have to consider what kinds of data can be transferred. We can extend the full marketing name to:

USB C T1 (audio)

USB C T1 (audio,video)

etc.

Obviously this is too long to have on the port itself, so we can stick with just the port type and transfer speed (eg. USB C T2) as the short name.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#164

Post by LeanderK »

I wonder whether it's a software or hardware problem? Let's say you have the thunderbolt connector, shouldn't all those supported standards (esp. the usb) then just be software problems? This does not make it easier for apples side, it might still be a huge undertaking, but then it would be upgradable in principle.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#165

Post by NoSorryCannot »

mmastrac wrote: post #142
akelly wrote: post #130

Earlier quoted context omitted.

Maybe we can call it a Universal Serial Bus

How many parallel differential pairs can you have before it's no longer serial? Hah.

You can have arbitrarily many, so long as the serial lanes are independent of each other. PCIe can have lots, for example. Because they are independent, they won't suffer from clockskew problems that made parallel signaling impractical at high speeds and it's often not required to connect all of the wires (e.g. an x16 card hanging out of an x8 or smaller slot) .

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#166

Post by gumby »

anticensor wrote: post #154
gumby wrote: post #78

Earlier quoted context omitted.

Sadly this might be more user friendly then the current setup. Even just a bit vector of the capabilities, expressed as a decimal or hex number, would be more comprehensible.

You would then get USB Type 61513 port and USB Type 48757 device, which could only communicate at Type 45151.

At least you’d know what you were getting.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#167

Post by tedunangst »

masklinn wrote: post #29
woodruffw wrote: post #5

The inability of the USB standards body to stick to a versioning scheme beggars belief: what in the world could "USB 3.1 Gen 2" possibly mean? Versions are free, why not simply name it "USB 3.2" and make the next one 3.3? "Gen 2" strikes me as the "Essay FINAL (final version 2).docx" of standards revisions.

> what in the world could "USB 3.1 Gen 2" possibly mean? Versions are free, why not simply name it "USB 3.2" and make the next one 3.3? USB 3.1 Gen 1 is the straight rebranding of USB 3.0, USB 3.1 Gen 2 is the "original" 3.1, which is 3.0 updated to a 10Gbps signalling rate (from 5), and a more efficient encoding (128/132, versus 8/10). But wait, there's worse! USB 3.2 Gen 1 is the same thing as USB 3.1 Gen 1 USB 3.2…

Wait until you read about old scsi standards.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#168

Post by faller »

colejohnson66 wrote: post #148
faller wrote: post #144

Earlier quoted context omitted.

> I'm not talking about the standards, but the marketing names. "USB 3.0" is now "USB 3.2 Gen 1" No, it's not. If you implement it from the legacy USB 3.0 spec then you don't care about it. It's SuperSpeed, and that's it. If instead you implement it to comply with the USB3.1 spec then you have two separate transfer modes specified in the 3.1 standard: the legacy Gen1 and the newly-added Gen2. If instead you implement…

> No, it's not. Yes, it is. > If instead you implement it to comply with the USB3.1 spec then you have two separate transfer modes specified in the 3.1 standard: the legacy Gen1 and the newly-added Gen2. No. If your device only supports 5 Gb/sec speeds, it's USB 3.0, yes. "SuperSpeed" and all that jazz. But with USB 3.2, it's now (magically) USB 3.2 Gen 1[0]: > Under this rebranding, the standard previously known as…

> No. If your device only supports 5 Gb/sec speeds, it's USB 3.0, yes.

That's not how things work.

Devices are implemented while targeting a standard.

If you implement a USB 3.0 device then you do not support any data transfer mode capable of doing more than 5Gb/s. If you're a customer looking for more than 5Gb/s and you see that a device is only USB3.0 then you already know that it won't cut it.

That's the whole point of this submission. M1 macs don't support USB 3.1, only USB 3.0. Why? because they patently don't support the transfer speeds made possible by the new data transfer mode introduced in USB 3.1.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#169

Post by [deleted] »

cycomanic wrote: post #30
woodruffw wrote: post #5

The inability of the USB standards body to stick to a versioning scheme beggars belief: what in the world could "USB 3.1 Gen 2" possibly mean? Versions are free, why not simply name it "USB 3.2" and make the next one 3.3? "Gen 2" strikes me as the "Essay FINAL (final version 2).docx" of standards revisions.

I think the should really just use sha hashes of the standard document, to avoid all this version name issues.

[deleted]

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#170

Post by rasz »

amelius wrote: post #60
masklinn wrote: post #41

Earlier quoted context omitted.

FWIW it's actually 500MB theoretical (ideal), because USB uses a 8/10 encoding[0], until 3.1 Gen 2 which switches to a 128/132 encoding[1]. So you have a 5Gb/s physical signal, then a 25% encoding overhead, for a raw data throughput of 537MB/s. Once framing and protocol overhead are taken in account, mid-400s effective is probably a good result. [0] https://en.wikipedia.org/wiki/8b/10b_encoding [1] https://en.wikiped…

What sucks, however, is that you can transfer 1TB to a USB drive correctly, and then finally have a bit-error that spoils the entire transfer and might even corrupt your drive. Happened to me several times during testing on different machines and with different cables and drives (luckily no real data was lost, but USB is now sort of banned from my office for use with external harddrives). Any sane protocol would be a…

This doesnt actually happen (single bit errors getting thru). USB 3.1 data is protected with https://en.wikipedia.org/wiki/Cyclic_redundancy_check#CRC-32... , same CRC as the one used in Ethernet.

https://www.rroij.com/open-access/implementation-of-link-lay...

USB 3 uses CRC-16, still more than good enough for single bit flips.

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