Is it possible to Switch off and back on the USB Hub?

Reading the SRM I have got quite confused with this issue. Maybe you
can give me some light with this.

We are using BB XM with Ubuntu 10.10 stripped from all the graphical

Our board seems to work fine. We run the complete system on batteries
and when the battery starts to be low (but not low enough yet)
randomly the USB Host fails when trying to use a webcam and all the
devices connected at the USB port fails (also the ethernet). With the
same remaining battery if we make a manual reset of the board the USB
ports seem to work fine for another hour before manually switching it
off. This condition is not happening allways, just randomly and
actually with low probabilities.

We thought in trying a reset of the hub without reseting the BB as in
the SRM it states at the page 148 that in order to reset the hub we
could power off and power on the USB hub.This sounded easy but I think
now this is so hard!

In order to reset the hub I found in Figure 38 that GPIO_56 should be
able to reset the PHY (USB3320), does this work? In table 10 however
it says it is the GPIO_147!! I assume this direction was wrong...

In figure 39 you can see that there is a HUB_RESET but we could not
find anywere from where this pin is coming. I guess this direction was
wrong becuase of the stated in the page 148.

in Figure 37 there is info about the LEDA/VIBRA.P. Is this the one I
should be looking at for power off and on the HUB?, how can I use this
from software? At page 97 it says that this chip is accessible from
the I2C1_SDA\L of the OMAP. So my next step is to read the TPS65950
specs to see which I2C commands do I have to send? can I do this with
root access just connectiong to /dev/I2C etc?

If I follow this pad, it means that in order to switch off the hub I
have to put the SHDN of the chip TL1963A to low or to up, but LEDA/
VIBRA-P is a PMW, so I have to put it to 0% duty cycle or to 100% duty
cycle. Is this right?

From here I am at a dead end because I have no clue of what I2C
messages I have to send through the I2C to the TPS65950, I could not
find any information about this in the reference manual of the TPS
(btw it is quite big document)...