On 02/22/2013 01:38 PM, John R Pierce wrote:
On 2/21/2013 12:43 PM, Robert Moskowitz wrote:
:[Firmware Warn]: Your BIOS is broken; DMAR reported at address fed90000 returns all ones!
I googled "Your BIOS is broken; DMAR reported at address fed90000 returns all ones!" and got some related results.
My search fu was weak. Very weak.
this bug report (on FC12) says... "yes, your bios is broken, but its not a bug, we worked around it" https://bugzilla.redhat.com/show_bug.cgi?id=896652
Well since Centos 6 is about equiv to F12, I guess I can 'live' with claim. But then, how to stop the constant error reporting?
on a similar/identical bug with Fedora FC17, someone suggested booting with iommu=off to work around this.
Where do I add this?
on a similar debian bug report, it was stated that this error only happened when the BIOS setting for "VT-d" was enabled. VT-d is only used to virtualized complete IO cards (like, dedicating a specified PCI-Express device to a given VM rather than handling it in the host and virtualizing the logical device). If your BIOS has an option to turn VT-d off, you might try that.
I did a bit of googling to figure out where this might be in my bios and found:
http://jaredlxl.blogspot.com/2009/04/enable-amt-on-hp-dc7800-dc7900.html
Which took me to the right place in the bios and I see it already disabled. So next is to try the iommu=off option.
Thanks for researching this for me.