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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

#201

Post by dwaite »

faller wrote: post #168
colejohnson66 wrote: post #148

Earlier quoted context omitted.

> 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 poi…

> 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.

M1 macs support USB4.

USB specs define multiple transmission modes and speeds from port to port over a cable that one can support. They define alt modes you can support.

Separately there are conformances and marks. E.g. if your cable supports transfer according to USB 3.2 Gen 2x2 in our lab, you can _market it_ as Superspeed 20Gbps, put the logo on the connectors, etc.

So the argument would be that Apple M1 doesn’t support Superspeed 10Gbps.

Which, as an aside, I’ll need a lot more than one person testing with a single (likely non-conformant) cable before I will believe.

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

#202

Post by dwaite »

colejohnson66 wrote: post #152
faller wrote: post #146

Earlier quoted context omitted.

> But USB 3.0 supported USB 2.0 and 1.0/1.1 speeds already without this "generation" garbage. No, not quite. What do you think the USB3.0 SuperSpeed is? Why, a brand new transfer mode. > If I plugged a USB 3.0 cable (9 pins) into a USB 2.0 (4 pin) hub, the device still worked at the lower speeds. You'd be glad to know that nothing changed in that regard with USB3.0, 3.1, and 3.2. In fact, the whole point of this subm…

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").

Your vendor should never have said 3.0 or 3.1 or 3.2. They should have said Superspeed.

There’s no point complaining that the engineering spec versioning strategy is confusing, when no consumers should have been exposed to it. The problem is squarely on manufacturers and the tech press.

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

#203

Post by dwaite »

colejohnson66 wrote: post #162
faller wrote: post #156

Earlier quoted context omitted.

> 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 "SuperSpe…

Versions are not speeds.

3.2 continues to describe everything in 3.0, which means it continues to describe how to make devices supporting 5 gbps over USB-A/B

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

#204

Post by grishka »

spankalee wrote: post #182
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…

The spec got a version bump from 3.0 to 3.1 and the new version of the spec added an additional transfer mode called "Gen 2". From that point of view it makes a lot of sense. You need to differentiate the spec version from the features talked about in the spec. From a marketing standpoint, it's terrible as most people need a simpler name and are incorrectly choosing the spec version. Marketing labels should just be "…

> You need to differentiate the spec version from the features talked about in the spec.

Maybe make a separate spec version for each transfer mode and require backwards compatibility. It's easy for the average person to understand "the higher the number, the newer the standard, the faster it goes". It's not as easy when there are 3 numbers, 2 of which are optional. If you have to use 3 numbers, you could at least make it look like a version number, so "3.1 Gen 2" would become simply 3.1.2. These are easy to understand too because everyone has at some point installed software updates.

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

#205

Post by [deleted] »

kcb wrote: post #100
Aaargh20318 wrote: post #77

Earlier quoted context omitted.

> as seen with the limit on external screens on some M1 models (…) I hope Apple fixes these issues soon It’s only the base M1 used in the low-end devices that has limited support for external screens. A MBPro with M1 Max can drive 3x6k (DP1.4) plus 1x4k(HDMI2.0). That seems like more than enough for a laptop. Sounds to me like these issues have already been fixed.

Apple doesn't make low-end devices.

[deleted]

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

#206

Post by dev_tty01 »

lowbloodsugar wrote: post #188

I have two USB 3.2 drives that don’t work at all on my M1, but work fine on my Intel Mac. On the M1 they show up in Disk Inspector but any attempt to read from them, or even eject them, gets the bouncy ball.

Is this perhaps just a file system formatting issue? Disk Utility (there is no Disk Inspector) should tell you how they have been formatted. You mentioned reading from them. Can you erase them? Tried different cables?

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

#207

Post by minhazm »

bombcar wrote: post #95
ChuckNorris89 wrote: post #85

Earlier quoted context omitted.

May I ask why? I assume you were aware of this limitation, as Apple was pretty clear in the specs about it, that it only supports one external monitor. If you pull the trigger on a purchase without reading the specs, then it's pretty much on you, no?

It didn’t become widely known until after the M1s had shipped - I was caught unexpected after someone at work couldn’t connect two to theirs.

But the comment says "M1-based iMac". The M1 iMac was released 6 months after M1 was first released with the Mac Mini, Macbook Air/Pro. I can understand if you bought the original M1 Air/Pro and were surprised it doesn't support more than 1 external display since it was indeed surprising behavior. But 6 months after the release of the chip is plenty of time to be informed on what you're buying.

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

#208

Post by derefr »

coryrc wrote: post #200
derefr wrote: post #198

Earlier quoted context omitted.

If most of the USB 3.1 spec is just USB 3.0, and you only need to refer to the USB 3.0 parts to build your device, then why not just build your device solely according to the USB 3.0 spec, and call it a USB 3.0 device? Compare/contrast: the 802.11 specification series. Each successive specification only lays out the unique new modes; with the expectation that devices support multiple specifications , where each speci…

> How else should you know whether your device can go at its full advertised speed? Just say what speed it supports using which technology. SuperSpeed at X Gbps, SuperSpeed+ at Y Gbps, high speed at 480 Mbps. You can only use a speed both support.

But in this case, say that a host supports only 3.2 Gen 2(x1), and a client device supports only 3.2 Gen 1x2. Both would advertise a relatively-higher speed, but it wouldn't just be that you'd get the lower of the two speeds; rather, you'd get a speed lower than either claim. And IMHO this isn't some weird exception; standards are often like this. This is is the reason people care to know exactly which subprotocols their devices are capable of negotiating, rather than just knowing the generation of support.

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

#209

Post by bmitc »

muro wrote: post #94
WithinReason wrote: post #20

Earlier quoted context omitted.

Same thing happened with HDMI 2.1, all new features were defined as optional so everyone who only supports the 2.0 feature set can claim HDMI 2.1 compliance

It does make sense that all new features are optional. E.g. 8k resolution does not need to be supported by your TV/monitor or VRR does as well not need to be supported by a Bluray player. As long as the devices can communicate and agree on signal, resolution etc. it's all fine. If anything is a mess, it's the cables, where you have to be careful to read whether high resolutions or ethernet or what passes through that…

Maybe that makes technical sense on paper, but in my experience, all these things quickly add up to it being impossible for a consumer or system integrator to know, beforehand, if something is going to work. I just setup a monitor with a built-in KVM, and it's practically impossible going by the specs supported (if you can find it) and whatever is in or not in the manuals to know a setup will work without just trying it. You have the monitor, webcam, two computers, keyboard, mouse, and other peripherals, and then you need to juggle HDMI, USB 2.x and 3.x, Display Port, and Thunderbolt. That doesn't even take into the fact that USB 2.x and 3.x are essentially physically incompatible due to interference at the connector site if they're nearby each other. There's also the myriad of ways on how something doesn't work as expected (4K video only over USB3.x or or a USB 3.x hub not having USB 2.x backwards compatibility or whatever else).

So, thousands of dollars of equipment working together cannot possibly be verified before purchase. It's insane.

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

#210

Post by Godel_unicode »

spankalee wrote: post #185
wolrah wrote: post #99

Earlier quoted context omitted.

> I think the USB naming is the result of not using marketers. No, it's specifically to give marketers what they want, which is the ability to advertise support for the latest version of the spec without actually having to improve the product. It's not USB-IF's marketers that want this, it's the vendors who pay USB-IF whose marketers want this.

Every backwards compatible spec would have this "problem". Either a new version of a spec says that all existing implementations are out of spec, or it add new optional features and existing implementations are that don't support them are still in spec. There's really no other option.

This is not an explanation of why the naming is a disaster. USB 1 devices work on USB 2 devices without there needing to be some insane renaming. Ditto USB 2 devices on USB 3 devices.

This naming was an entirely unforced error, and should be called out as such at every opportunity to keep it from happening again.

Edit: if you want another example of a spec with good names, checkout WiFi 6. They realized that no normal person could reason about whether 11n or 11ac was better, so they changed the naming scheme to make it obvious what was going on.

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