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Usb hub issues

Community Veteran
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Registered: 16-02-2009

Usb hub issues

Anybody come across an issue where a hub works fine on one pc but not another?
I got  a new 4 port hub for use with my new pi-zero, but when plugged in via an adapter or an org cable it isn't recognised.
Plug it in to the my pc and it sees it fine.
Pi is powered by a 6A usb charger unit, so no lack of power. I currently have a different hub plugged in with no issues so it isn't the hardware on the pi side.
16 REPLIES
Community Veteran
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Registered: 24-10-2013

Re: Usb hub issues

is it a powered usb hub?
i suspect if it isn't then that'll be the problem
Community Veteran
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Re: Usb hub issues

It's not powered but so what. The other hub (working) isn't powered either.
All that was plugged in as a wifi & keyboard, not like a heavy power draw.
I also tried with nothing plugged in, same issue nothing seen.
Community Veteran
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Re: Usb hub issues

so what? well it's entirely possible that the hub that doesn't work needs a little bit more juice to work on its own than the other one does.
not all usb hubs are created equally or of equal build quality.
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Re: Usb hub issues

Plugging it in via a "charger doctor" shows it taking 9mA with a BT dongle plugged in, with just the BT dongle in the CD it shows 7mA
So not a case of it taking too much power.
DaveyH
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Re: Usb hub issues

I have a (powered) Hub that doesn't work with any of my Pis and caused boot loops on one of them but works perfectly fine  on my PCs.
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Re: Usb hub issues

So must be an issue with the usb interface on pi's then. Verrrrrry stange.
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Re: Usb hub issues

I have a mini rii keyboard with touchpad:

Despite seeing many people saying online they can just plug it into their pi and it works instantly... do you think mine ever worked? Absolutely not. I couldn't find anyone else reporting it not working either in order to get it working... so i stopped trying  Cheesy
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VileReynard
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Re: Usb hub issues

AFAIK A "standard" type B needs 1A at 5V - and is very fussy that the full voltage requirement is met.

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Re: Usb hub issues

I thought it was 760mA?
That said.. mine is powered from a 500mA supply so that could explain a thing or two  Cheesy
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Community Veteran
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Re: Usb hub issues

If you read the first post it clearly says I am using a PI ZERO. Something like 180mA needed. I am also powering it from a 6A USB Charger, No lack of power. Yes it can pump 6A down a cable, or 6*1A or any combo, one of the reasons I bought it to replace my many usb chargers. (6 usb ports, capable of supplying up to 6A in total)
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Re: Usb hub issues

You might be able to supply up to 6A to the Pi Zero, but that doesn't mean the Pi Zero can pump 6A out of its USB port. I thought a USB port is normally limited to supplying a maximum of 500mA, and that was part of the USB2 specification, and not just something that could be bypassed by wiring it up to a source that can supply more current. USB devices indicate the maximum amount of power they need, my TP-Link TL-WN822Nv3 that I use with my Pi2, indicates that it uses the full 500mA. I thought the USB controller would add up the total power required by all devices connected to a port, and check if the total could be supplied.
I've got a 7 port USB hub that can work with or without its power supply. However, the hub always indicates that it is self powered, and not bus powered, even when operating without it's own power supply. That is obviously wrong, but I guess it was easier to make it like that than have it report the correct status depending on if its power supply is plugged in or not. It's got a red LED labelled "self power" too, which is on regardless of how the hub is actually being powered. lsusb -v will display a lot of details about USB devices, including how they say they are powered and the max power they claim to need.
Anyway, there's probably some clue as to why it doesn't work in the dmesg output, so you could plug in the hub that doesn't work, then unplug it and plug in whatever you need to read the log messages. Or compare the lsusb -v output of each hub.
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Re: Usb hub issues

I wasn't suggesting that the pi would use all 6A I was just saying that there was plenty of power available.
I posted the current used by the hub connected to my pc using a charge doctor. With a bt dongle 9mA with BT dongle direct 7mA so that suggests the hub is taking 2mA.
If I plug all the items into the hub they are recognised by the pc so the hub works.
As has been said must be an issue with Debian on the pi. It is annoying as I bought the hub specifically for the pi.
lsusb on here shows it as:
Bus 006 Device 002: ID 0a05:7211 Unknown Manufacturer hub
which is probably why it isn't recognised on Debian,
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Re: Usb hub issues

The "Unknown Manufacturer" string there makes absolutely no difference to anything else whatsoever. It's just the string retrieved by looking up the numeric IDs in the text file /usr/share/hwdata/usb.ids or wherever it's located in Debian. You could edit the usb.ids file and write in whatever name you like.
Perhaps I didn't explain it clearly enough. What I meant was, no matter how much power you can supply to the Pi, the Pi itself may have its own limit on how much power it can supply from its USB port. Anyway, the problem might not be how much power the devices are actually using, it could be how much power they indicate they need to the computer over the USB protocol.
Community Veteran
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Re: Usb hub issues

As I said a different hub works fine with the pi, using the same things plugged into it.
The wifi & keyboard neither exceed 100mA draw in total.
It was just this hub that I bought FOR the pi doesn't work and it was the first time I have come across a hub not working on anything. (that supports hubs)