usb/180254: FreeBSD 9.1 on 384GB memory server

[Mool]

>Number:         180254
>Category:       usb
>Synopsis:       FreeBSD 9.1 on 384GB memory server
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-usb
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jul 04 09:40:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Mool
>Release:        FreeBSD 9.1
>Organization:
>Environment:
FreeBSD 123.xxx.com 9.1-RELEASE-p3 FreeBSD 9.1-RELEASE-p0 
>Description:
Hi ALL , 

I had two 384GB memory server (Cisco UCS-240M3 & Supermicro X9DRi-LN4F+)

When I using FreeBSD-9.1-RELEASE-amd64-bootonly.iso disc boot 
boot script will stop at <mount_root> .
Looks like USB CDROM can't find ... and USB keyboard can't type any key. 

console message is 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 
usbd_ctrl_transfer_setup: could not setup default USB transfer 


I try to booting from cdrom use FreeBSD-8.3-RELEASE-amd64-bootonly.iso is okay... Debian / Ubuntu is okay . 

Other way is.. plug out memory to 288GB , FreeBSD 9.1 boot is normal ...

So.. FreeBSD 8.3 on 384GB memory server is okay , but FreeBSD 9.1 is not.
>How-To-Repeat:
384GB memory
>Fix:
At boot menu 

[2] escape to loader prompt


OK  set kern.maxbcache="64M" 
OK  boot

>Release-Note:
>Audit-Trail:
>Unformatted: