[Q] USB is very slow. Is this a known bug?

Ezequiel Garcia elezegarcia at gmail.com
Sat Sep 22 16:25:33 EDT 2012

Hi Greg!

On Sat, Sep 22, 2012 at 5:04 PM, Greg KH <greg at kroah.com> wrote:
> On Sat, Sep 22, 2012 at 04:03:42PM -0300, Ezequiel Garcia wrote:
>> Hello,
>> Has anyone had problems with usb bandwidth?
>> According to this page:
>> http://elinux.org/RPi_Performance#USB_bus
>> The rpi can achieve 30 Mb/s.
> With a tail wind fall downhill, it maybe can get that fast.


>> However, a user has reported a much lower bandwidth, as low as 2 Mb/s.
>> See here:
>> https://github.com/ezequielgarcia/stk1160-standalone/issues/5#issuecomment-7560214
> Quite common, most USB storage devices are really really slow.  Also,
> iso data is quite different for this controller, it's amazing that it
> even works.

The user reports he made the test with a "fast" device, meaning
that same device can output 30 Mb/s in his laptop (see same link).

> Heck, it's amazing that USB works at all on this hardware in the first
> place, Just be happy you are getting _any_ data from it :)
>> Is this a known bug? Has anyone seen using vanilla kernel?
> You can't use a "vanilla" kernel on the rpi right now, especially for
> USB.
>> Are there any ideas for what might be going on?
> Yes, the hardware is broken, the drivers are broken, and I would not
> recommend anyone wanting to do any real USB data transfers to use this
> platform at all.  Seriously.  Go complain to Broadcom if you want to see
> this fixed, they are the ones with the specs that we can not get access
> to.

Mmmm, I see.

For some reason (cheapness? crazyness?)
there are a few users out there wanting to do video streaming
with their rpi and they want to use stk1160 devices.
Thus my question.

I don't want to bother you asking: what do you mean by "hw is broken",
"drivers are broken"?
But ... is it related to the fact eth and usb goes through same bus?


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