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usrbinroy
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The USB Hub / Internet problem

Sun Jul 22, 2012 11:11 am

Hello All

Using the latest download from the RaspberryPi site
Self powered 4 port Belkin USB Hub with keyboard and mouse plugged into it
Power supply from RS Components 1.2 amp output

Pi is working fine but when using either of the supplied browsers they are unable to resolve the requested URL

A search on this forum revealed one other post with same problem and for me same solution : discard USB hub and plug keyboard and mouse in direct. Internet then works fine.

It would seem this is a known bug. My question is are there any workarounds? For example is there a hub that does work? Does getting a different power supply solve the problem?

Is the underlying problem with the Pi's (underpowered?) USB ports i.e. hardware or is there a software conflict problem with the ethernet plug?

TIA for any comments

Roy

ferrymanr
Posts: 61
Joined: Fri Mar 16, 2012 11:09 pm

Re: The USB Hub / Internet problem

Mon Jul 23, 2012 9:07 pm

I have the impression eth0 sits on USB. When I run 'dmesg' the sequenc seems to be eth0, then USB port neares PCB anthe top USB port. Perhaps someone can tell me if eth0 really is tied in with USB? If so it might explain a number of problems which I associate with interrupt handling. Lots of interaction between eth0, sound cards, USB to RS-232 converters and keyboard, even when each external USB device is externally powered.

plugwash
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Re: The USB Hub / Internet problem

Mon Jul 23, 2012 10:53 pm

ferrymanr wrote:I have the impression eth0 sits on USB. When I run 'dmesg' the sequenc seems to be eth0, then USB port neares PCB anthe top USB port. Perhaps someone can tell me if eth0 really is tied in with USB?
It is.

The Ethernet port and the two USB ports on the Pi go to a SMSC LAN9512 USB hub with ethernet chip. This then connects back to the SOC via a single USB connection.
If so it might explain a number of problems which I associate with interrupt handling. Lots of interaction between eth0, sound cards, USB to RS-232 converters and keyboard, even when each external USB device is externally powered.
The real problem seems to be that the USB contoller on the Pi's SOC was really designed to do a device port on a phone or similar and had host funcionality bolted on as an afterthought.

I've heard some hubs get on better with the Pi than others. Unfortunately it's a bit of a crapshoot because even two hubs in identical boxes can have different chipsets.

I'd check voltages throughout the system too, in particular i've head of some powered hubs whose power supplies are a total joke capable of doing little more than lighting the LED on the hub.

ferrymanr
Posts: 61
Joined: Fri Mar 16, 2012 11:09 pm

Re: The USB Hub / Internet problem

Mon Jul 23, 2012 11:26 pm

plugwash wrote: I'd check voltages throughout the system too, in particular i've head of some powered hubs whose power supplies are a total joke capable of doing little more than lighting the LED on the hub.
Rubbish is an understatement. Some of these 'wall warts' give well over 6.5V off load down to less than 4.5V at rated current. As I run everything, including my amateur radio equipment, from a 13.8V float charged battery supply I use individual industrial switch mode regulators which are more efficient than linear regulators to get my 5V , these are adjusted for 5.0V on the RPi or hub etc. as power leads can be lossy too. A lot of people check their voltages off load which is a big mistake. The only way to test is on load and on the board. I also found a lot of high frequency ripple on many cheap supplies, around 200mV p-p on one Chinese offering.

marsman2020
Posts: 72
Joined: Sun May 20, 2012 11:26 pm

Re: The USB Hub / Internet problem

Tue Jul 24, 2012 1:26 am

*Assuming* you have a good power supply (If you are in the US, I recommend the HP Touchpad wall wart, which is 5.3V/1A. The extra voltage helps make up for the polyfuses. I checked mine on an oscilliscope under load. HP has them for $5. Don't use the USB cable that comes with it though, is has very thin wire with a high resistance).....

My Logitech wireless mouse (which works with every other machine I've ever plugged it into) caused issues with the network when plugged into a hub, but not when plugged directly into the Pi.

I have found 3 potential work-arounds for this issue:
-Most reliable solution: use a wired keyboard and wired mouse with a known low power draw (no USB hubs or lights on the keyboard is a good start) connected directly to the Pi. I used a cheapo keyboard and mouse from Monoprice.
-Potentially unreliable solution, but worth trying if you need an additional USB port: Use the same wired keyboard and mouse on a known-OK hub
-Experimental but maybe working solution, for highly experienced users only - try the patch popcornmix posted at https://github.com/raspberrypi/linux/issues/29 and let him know if it works for you so it might get added to the Pi kernel. (It worked for me and fixed the issues with the wireless mouse).

timmoore46
Posts: 266
Joined: Tue Jul 17, 2012 4:36 pm

Re: The USB Hub / Internet problem

Tue Jul 24, 2012 11:42 am

Another cry of pain !

I'm using Raspbian and if I plug my mouse and keyboard into the R Pi all is well.

I use NetSurf browser no probs with the ethernet connection.

Reboot with a 7 port Powered Hub (mouse and keyboard plugged into the hub) and zero internet ! Now I built a regulator (7805) and monitor the current taken and all is OK with 5.03volts offered. But zero internet !

What do I do next ? Change hubs until I find one that works ?

A very puzzled,

:? :? :? :? :? :?

Tim

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