I have been attempting to get a working USB 3 external harddrive 
subsystem.  Thus far, no go.

Here is what I have found:

1.  kernel 2.6.38.6-26.rc1.fc15.x86_64 works fine for USB 3, but 
requires gcc 4.6 to build any kernel modules; RHEL 6 (SL 6, CentOS 6) 
uses gcc 4.4.  Thus, neither the Nvidia nor VirtualBox modules will 
build on on a RHEL 6 system.

2.  kernel 2.6.33.3-85.fc13.x86_64 that was built with gcc 4.4 works, 
but only partially -- please see point 3.

3.  After installing both of the above kernels, kernel 
2.6.32-131.2.1.el6.x86_64 now functions essentially the same as 
2.6.33.3-85.fc13.x86_64 .  The device is recognized and /dev/sde and the 
partitions thereunder /dev/sde1 ... are created.  However, no automount 
points are created that were created with 2.6.38.6-26.rc1.fc15.x86_64 .
Moreover, fdisk /dev/sde fails.  A reading of dmesg shows numerous 
exceptions and diagnostics that are documented in USB 3 linux kernel 
development hits during a web search and that evidently were fixed in 
later kernels (such as 2.6.38.6-26.rc1.fc15.x86_64 ).  I am not going to 
reproduce these here, but suffice it to say that the /dev/sde set 
appears, vanishes as evidenced by the output of /ls/dev/sd* and then 
reappears.

Note that all of the hardware and systems commands, etc., work on a USB 
2 port on this system.

An attempt to build from source 2.6.38.6-26.rc1.fc15.x86_64 using the 
gcc 4.4 system of SL6 is my next step, rpmbuild --rebuild 
kernel-2.6.38.6-26.rc1.fc15.src.rpm  .

Yasha Karant