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.
Am 22.02.2013 21:10, schrieb Robert Moskowitz:
On 02/22/2013 03:04 PM, Reindl Harald wrote:
Am 22.02.2013 20:58, schrieb Robert Moskowitz:
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.
Nah. Just go into GRUB's kernel command line edit mode during boot and remove the offending option to get the system up. Then you can edit grub.conf at your leisure.
On 02/24/2013 06:39 AM, Tilman Schmidt wrote:
Am 22.02.2013 21:10, schrieb Robert Moskowitz:
On 02/22/2013 03:04 PM, Reindl Harald wrote:
Am 22.02.2013 20:58, schrieb Robert Moskowitz:
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.
Nah. Just go into GRUB's kernel command line edit mode during boot and remove the offending option to get the system up. Then you can edit grub.conf at your leisure.
The one time it happened to me, this did not work. I can't find the details, but I think I had some other option set and I could not get into this. I seem to recall the problem was the video option and driver for the DecTop that had the Anode chip. For install, I even had to build a special iso with the proper drivers in. But for a couple years, those DecTops were fun to play with. One of the first fanless affordable systems; at the time I was working with a small group that was looking into a home server. Something that is commodity now.
But I will remember this for the next time!
Oh, I recently pulled one out of the dustbin to put XP on it as a client test system. Around here, I need to watch my pennies and I try to use what I have...
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Robert Moskowitz -
Tilman Schmidt