Re: 2.6.29: can't resume from suspend with DMAR (intel iommu) enabled

[Kyle McMartin <kyle@redhat.com>]

On Tue, Mar 24, 2009 at 01:36:46PM -0700, Yu, Fenghua wrote:
> >
> >(Cc:s added)
> >
> >* Andrew Lutomirski <amluto@gmail.com> wrote:
> >
> >> On vanilla 2.6.29 (on Ubuntu 8.10), on a Lenovo x200s, my system
> >> is completely hosed on resume.  It appears that even hard disk IO
> >> didn't work (trying to do *anything* including getting a dmesg
> >> trace just spewed sda io errors to the console).  Hence no trace.
> >> I did an alt-sysrq-b and the screen went blank and the machine
> >> just started beeping at me.
> >>
> >> Resume works much better with intel_iommu=off.  (I remember seeing
> >> a patch go by that purported to fix resume with IOMMU enabled, but
> >> it didn't work for me.)
> >>
> >> I'd be happy to try to make a better bug report if anyone has any
> >> bright ideas.
> >
> >i have a Lenovo T500 that does not even boot with with DMAR enabled
> >in the BIOS (it's default-off), i get this panic in early bootup:
> >
> >    DMAR hardware is malfunctioning
> >
> >So i dont get to test suspend/resume ;-)
> >
> Current kernel doesn't have iommu suspend/resume support yet. I'll send out suspend/resume patches today or tomorrow. Hope that will help.
> 

Heh, awesome, someone could have brought this, uhm, subtle, weakness when
things were getting defaulted on...

regards, Kyle