Weird fan noise with usb activity

[hiren panchasara]

Hi All,

I have this machine running current:

Copyright (c) 1992-2013 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 10.0-CURRENT #0 r252476M: Mon Jul  1 15:20:47 PDT 2013
    root@:/usr/obj/usr/home/hirenp/head/sys/GENERIC amd64
FreeBSD clang version 3.3 (tags/RELEASE_33/final 183502) 20130610
CPU: Genuine Intel(R) CPU  @ 2.00GHz (1995.24-MHz K8-class CPU)
  Origin = "GenuineIntel"  Id = 0x206d2  Family = 0x6  Model = 0x2d
Stepping = 2
  Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0x1fbee3ff<SSE3,PCLMULQDQ,DTES64,MON,DS_CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,DCA,SSE4.1,SSE4.2,x2APIC,POPCNT,TSCDLT,AESNI,XSAVE,OSXSAVE,AVX>
  AMD Features=0x2c100800<SYSCALL,NX,Page1GB,RDTSCP,LM>
  AMD Features2=0x1<LAHF>
  TSC: P-state invariant, performance statistics
real memory  = 60129542144 (57344 MB)
avail memory = 55965908992 (53373 MB)
Event timer "LAPIC" quality 600
ACPI APIC Table: <INTEL  S2600CP>
FreeBSD/SMP: Multiprocessor System Detected: 24 CPUs
FreeBSD/SMP: 2 package(s) x 6 core(s) x 2 SMT threads

beefy% uname -a
FreeBSD beefy.corp.yahoo.com 10.0-CURRENT FreeBSD 10.0-CURRENT #0
r252476M: Mon Jul  1 15:20:47 PDT 2013
root@:/usr/obj/usr/home/hirenp/head/sys/GENERIC  amd64
beefy%

and everynow and then when machine is not doing anything or none is
touching it, the fans go mad for 5-9 seconds and make real loud noise.
Whenever that happens, I see following in dmesg:

ukbd0: at uhub2, port 4, addr 3 (disconnected)
ums0: at uhub2, port 4, addr 3 (disconnected)
usbd_setup_device_desc: getting device descriptor at addr 3 failed,
USB_ERR_TIMEOUT
usbd_setup_device_desc: getting device descriptor at addr 3 failed,
USB_ERR_TIMEOUT
ugen1.3: <American Megatrends Inc.> at usbus1 (disconnected)
ugen1.3: <American Megatrends Inc.> at usbus1
ukbd0: <Keyboard Interface> on usbus1
kbd2 at ukbd0
ums0: <Mouse Interface> on usbus1
ums0: 3 buttons and [Z] coordinates ID=0

beefy% sudo usbconfig
ugen0.1: <EHCI root HUB Intel> at usbus0, cfg=0 md=HOST spd=HIGH
(480Mbps) pwr=SAVE (0mA)
ugen1.1: <EHCI root HUB Intel> at usbus1, cfg=0 md=HOST spd=HIGH
(480Mbps) pwr=SAVE (0mA)
ugen1.2: <product 0x0024 vendor 0x8087> at usbus1, cfg=0 md=HOST
spd=HIGH (480Mbps) pwr=SAVE (0mA)
ugen0.2: <product 0x0024 vendor 0x8087> at usbus0, cfg=0 md=HOST
spd=HIGH (480Mbps) pwr=SAVE (0mA)
ugen1.4: <HP Basic USB Keyboard CHICONY> at usbus1, cfg=0 md=HOST
spd=LOW (1.5Mbps) pwr=ON (100mA)
ugen1.3: <Virtual Keyboard and Mouse American Megatrends Inc.> at
usbus1, cfg=0 md=HOST spd=FULL (12Mbps) pwr=ON (0mA)
beefy%

I am not sure at all how to make sense of these things. Please let me
what more information I can provide.

Thanks,
Hiren

(I am not on this list so keep please me in the loop)