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.