bhatcher
Posts: 3
Joined: Thu Feb 18, 2021 7:41 pm

RPi USB Compliance

Sat Feb 20, 2021 12:11 am

Have any RPi products gone through the USB-IF compliance process? For example I see on the RPi Zero W page:
Compliance
The Raspberry Pi Zero W has undergone extensive compliance testing, and meets the following European standards:
  • Electromagnetic Compatibility Directive (EMC) 2014/30/EU
  • Restriction of Hazardous Substances (RoHS) Directive 2011/65/EU
View and download global compliance certificates for Raspberry Pi products.
However I don't see anything about USB compliance. I know the RPi 4 originally was non-compliant on its USB-C interface, so this implies that RPi does not pass USB-IF compliance before releasing products.

I realize there is some distinction between being merely USB compliant as in "it adheres to the spec" vs being "capital C" compliant and going through the testing process through USB-IF.

Also, is anyone aware of any products based on the RPi that have sought out USB-IF compliance?

W. H. Heydt
Posts: 14408
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: RPi USB Compliance

Sat Feb 20, 2021 1:41 am

The "non-compliance" of the USB-C *power* connector (which can be used as a USB 2 device) was strictly a matter of not working with PD PSUs and e-marked cables.

However, I will assert with some confidence that the USB ports on B-series Pis are *not* compliant as a Pi can't guarantee to supply the specified current to downstream USB devices. The most any Pi can provide to the 4 USB ports is 1.2A. For the Pis with 4 USB ports, the spec would require a combined 2A and for the Pi4B, with 2 USB 2 and 2USB 3, it would have to supply 2.8A.

As for compliance with RF emissions standards...that's what the RPT has them tested for.

LTolledo
Posts: 4814
Joined: Sat Mar 17, 2018 7:29 am
Location: Anime Heartland

Re: RPi USB Compliance

Sat Feb 20, 2021 9:56 am

is this another "witch hunt"? :shock:
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 28358
Joined: Sat Jul 30, 2011 7:41 pm

Re: RPi USB Compliance

Sat Feb 20, 2021 10:32 am

Don't think so.

We've never claimed that we passed this particular testing; we are happy that on the whole, the USB just works!
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed.
I've been saying "Mucho" to my Spanish friend a lot more lately. It means a lot to him.

LTolledo
Posts: 4814
Joined: Sat Mar 17, 2018 7:29 am
Location: Anime Heartland

Re: RPi USB Compliance

Sat Feb 20, 2021 10:42 am

jamesh wrote:
Sat Feb 20, 2021 10:32 am
....we are happy that on the whole, the USB just works!
and that is most important....
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"

W. H. Heydt
Posts: 14408
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: RPi USB Compliance

Sat Feb 20, 2021 5:47 pm

jamesh wrote:
Sat Feb 20, 2021 10:32 am
Don't think so.

We've never claimed that we passed this particular testing; we are happy that on the whole, the USB just works!
So am I, given the early teething problems. And I'm sure that the Pi USB ports *are* in compliance when it comes to RF emissions, and that's the important part.

bhatcher
Posts: 3
Joined: Thu Feb 18, 2021 7:41 pm

Re: RPi USB Compliance

Mon Feb 22, 2021 6:16 pm

jamesh wrote:
Sat Feb 20, 2021 10:32 am
Don't think so.

We've never claimed that we passed this particular testing; we are happy that on the whole, the USB just works!
Not suggesting it's been claimed, just curious! USB-IF has a "certification by similarity" program which allows products similar to existing compliant ones to streamline the compliance process. If people used the RPi as the basis for a commercial product, it would make that process a lot easier. Thanks for confirming my suspicions!

jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 2548
Joined: Thu Jul 11, 2013 2:37 pm

Re: RPi USB Compliance

Tue Feb 23, 2021 12:32 pm

There is basically no such thing as a "compliant" USB device (or controller). The enormous numbers of workarounds, quirks, special-cases, fudges and straight up hacks in every part of the USB driver stack in Linux is a testament to this fact.

Even if you had a mystical "compliant" USB host, it would fail interop with a good portion of unusual devices.

The best you can hope for is a maximal set of interoperable devices if you are a host, and a maximal compatibility with host controllers if you are a device.
Rockets are loud.
https://astro-pi.org

W. H. Heydt
Posts: 14408
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: RPi USB Compliance

Tue Feb 23, 2021 5:34 pm

jdb wrote:
Tue Feb 23, 2021 12:32 pm
There is basically no such thing as a "compliant" USB device (or controller). The enormous numbers of workarounds, quirks, special-cases, fudges and straight up hacks in every part of the USB driver stack in Linux is a testament to this fact.

Even if you had a mystical "compliant" USB host, it would fail interop with a good portion of unusual devices.

The best you can hope for is a maximal set of interoperable devices if you are a host, and a maximal compatibility with host controllers if you are a device.
Fair enough...and--so far--my experience is that Pis do quite well in those areas.

I read the OP as being concerned with RF interference compliance (in that there shouldn't be any outside legal limits) and I have every confidence in you folks that that is tested and does meet standards.

bhatcher
Posts: 3
Joined: Thu Feb 18, 2021 7:41 pm

Re: RPi USB Compliance

Tue Mar 02, 2021 12:27 am

There is basically no such thing as a "compliant" USB device (or controller). The enormous numbers of workarounds, quirks, special-cases, fudges and straight up hacks in every part of the USB driver stack in Linux is a testament to this fact.

Even if you had a mystical "compliant" USB host, it would fail interop with a good portion of unusual devices.

The best you can hope for is a maximal set of interoperable devices if you are a host, and a maximal compatibility with host controllers if you are a device.
I'm not asking if a device functions perfectly with all USB devices ever made. I'm referring to certification for compliance by the USB-IF.

Return to “Advanced users”