[CentOS] Warning: Your BIOS is broken

[Robert Moskowitz]

On 02/22/2013 03:04 PM, Reindl Harald wrote:
>
> Am 22.02.2013 20:58, schrieb Robert Moskowitz:
>> Kernel param.  I really should have caught that.
>>
>> So I was all ready to edit grub.conf and then slapped my hand.
>> You TEST it out first, adding the command at boot time.  ARGH!
> one option
>
>> Once before (5+ years back) I had to add a kernel param and did it wrong and
>> it was a big recovery challenge
> what is the challenge?
> there is no difference add or remove a param at boot

If you get the option wrong and the system will now not boot?  Then you 
have to boot from a recovery CD, mount your harddrve /boot and edit out 
the change from grub.conf and try again.  All the time you SHOULD have 
been working on something else.

>
>> But as I read up on this option, it does not sound like something I want
>> to globally turn off just to stop a supposedly annoying
>> message (if they have indeed worked around it, and my new DNS server is running with this OK)
> and you looked at the other options?
> "intel_iommu=igfx_off" maybe a good idea
>
> 	intel_iommu=	[DMAR] Intel IOMMU driver (DMAR) option
> 		on
> 			Enable intel iommu driver.
> 		off
> 			Disable intel iommu driver.
> 		igfx_off [Default Off]
> 			By default, gfx is mapped as normal device. If a gfx
> 			device has a dedicated DMAR unit, the DMAR unit is
> 			bypassed by not enabling DMAR with this option. In
> 			this case, gfx device will use physical address for
> 			DMA.
> 		forcedac [x86_64]
> 			With this option iommu will not optimize to look
> 			for io virtual address below 32 bit forcing dual
> 			address cycle on pci bus for cards supporting greater
> 			than 32 bit addressing. The default is to look
> 			for translation below 32 bit and if not available
> 			then look in the higher range.
> 		strict [Default Off]
> 			With this option on every unmap_single operation will
> 			result in a hardware IOTLB flush operation as opposed
> 			to batching them for performance.
> 		sp_off [Default Off]
> 			By default, super page will be supported if Intel IOMMU
> 			has the capability. With this option, super page will
> 			not be supported.
>
I will look at these closely and figure out what course to test. The 
sabbath is almost here, so got a hard stop time.