Boot message:IOMMU failed to map dmar0 <SOLVED>

[MrBob22]

I keep getting this particular error message and dont really know what to do about it. A search for this error does not come up with much, so I am posting this for the gurus who know about IOMMU and what I might do to fix this.
Here is the result of a dmesg command I ran:

Code: Select all

dmesg | grep -e DMAR -e IOMMU
[    0.000000] ACPI: DMAR 00000000b8dd6da0 000E8 (v01 ALASKA    A M I 00000001 INTL 00000001)
[    0.000000] Your BIOS is broken; DMAR reported at address fed90000 returns all ones!
[    0.015314] dmar: IOMMU: failed to map dmar0
[    0.015316] dmar: parse DMAR table failure.


I dont like it when it says my Bios is Broken! Anybody have some suggestions?
Here is my set up:
-Computer-
Processor : 4x Intel(R) Core(TM) i3-2100 CPU @ 3.10GHz
Memory : 3795MB (768MB used)
Operating System : Linux Mint 14 Nadia
User Name :
Date/Time : Sun 02 Jun 2013 03:51:52 PM EDT
-Display-
Resolution : 1920x1080 pixels
OpenGL Renderer : Mesa DRI Intel(R) Sandybridge Desktop
X11 Vendor : The X.Org Foundation
-Multimedia-
Audio Adapter : HDA-Intel - HDA Intel PCH
-Input Devices-
Power Button
Power Button
Microsoft Comfort Curve Keyboard 2000
Microsoft Comfort Curve Keyboard 2000
USB Optical Mouse
HDA Intel PCH HDMI/DP,pcm : 3=
HDA Intel PCH Line
HDA Intel PCH Front Mic
HDA Intel PCH Rear Mic
HDA Intel PCH Front Headphone
HDA Intel PCH Line Out Side
HDA Intel PCH Line Out CLFE
HDA Intel PCH Line Out Surround
HDA Intel PCH Line Out Front
-Printers (CUPS)-
Stylus-Photo-1400 : <i>Default</i>
-SCSI Disks-
ATA WDC WD10EALS-002
ATA WDC WD10EZEX-00R
_NEC DVD_RW ND-3500AG

Thanks in advance, MrBob22

[MrBob22]

OK, so I did find out a little bit about IOMMU. Its short for Input/Output Memory Management Unit, and is a way to connect a DMA-capable I/O bus to the main memory. This allows addressing memory by mapping it rather than by direct physical address. This is supposed to give some advantages for addressing large memory segments that are not necessarily contiguous (the mapping is done by the IOMMU I guess) and allows 32 bit computers with PAE to address memory beyond the 4Gb limit. AMD calls their system Hyper-transport architecture and Intel calls theirs VT-d. Anyway, it looks like you have to have a CPU that supports IOMMU and I dont see VT-d listed in the CPU Flags for my chip (i-3 2100.) So maybe the Linux Kernel is trying to use IOMMU but the system is not supporting it? This is a bit deeper into the micro than I ususally dive...Thanks to all who have looked at this...

[MrBob22]

Solved!
I was digging through the BIOS screen, and something I had totally missed popped up today. VT-d can be enabled/disabled in the bios settings, so when I disabled VT-d, the error message about IOMMU went away. Woo hoo.