8.0-RC1: AMD CS5536 (Geode) USB 2.0 controller strange behavour

[Eugene Grosbein]

On Sun, Sep 27, 2009 at 10:31:38PM +0800, Eugene Grosbein wrote:

> > %dd if=/dev/zero bs=64k of=/dev/da0 count=1000
> > 
> > It started to work, meantime iostat output was:
> > 
> >  63.62  17  1.05
> >   0.00   0  0.00
> >   0.00   0  0.00
> >   0.00   0  0.00
> >   0.00   0  0.00
> >   0.00   0  0.00
> >  64.00   2  0.15
> >  62.31  83  5.06
> >   0.25   0  0.00
> >   0.00   0  0.00
> >   0.00   0  0.00
> > ^C

I've repeated the test with my USB flash drive formatted as FAT32.
It gives the same result: for ICH7-based system I get 26 megabyte/s
file writing speed and for AMD CS5536 it suffers from long periods of inactivity
while writing data, hence very low awarage writing speed.

It seems the root of the problem is in the interaction
between USB stack and AMD CS5536 (Geode) USB 2.0 controller
and not in media devices themselves.

Any more hints please?

Eugene Grosbein