Re: Powerdown problem on XEN | ACPI S5

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Aug 14, 2013 at 11:56:10PM +0200, Atom2 wrote:
> Hi Ben & Konrad,
> thanks for your suggestions. I have to admit, I don't fully
> understand the commit system yet and don't know how to apply that to
> my gentoo sources. But I read through the thread that Ben has posted
> and thought, given that Ben had linked the issue to the Intel i915
> driver, I'll try something that crossed my mind:
> 
> lspci lists the Intel IGD as follows:
> 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200
> Processor Family Integrated Graphics Controller (rev 09)
> 
> So my thought process was if the IGD is to blame, I'll just exclude
> that from the dom0 by adding it to the xen-pciback.hide list on the
> module line of grub. This line now reads as follows (NOTE: all other
> devices except the first one (00:02.0) have been there already
> before my latest try):
> 
> module  /boot/gentoo-3.9.5-hardened-xen rootfstype=ext4 root=/dev/sda6 \
> 
> xen-pciback.hide=(00:02.0)(00:1b.0)(02:00.0)(03:00.0)(04:00.0)(05:00.0)(06:00.0)(09:00.0)(09:02.0)(0a:08.0)(0a:09.0)(0a:0a.0
> )(0a:0b.0)
> 
> Clearly this meant that after the dom0 (gentoo hardened) was
> started, there was no more console output available. So I had to use
> ssh to login. But once I started a (remote) 'shutdown -h now' from
> the login bash and ... the system actually powerd off.
> 
> I guess this really proves that the (in-kernel) i915-driver which,
> given that the IGD is no longer available, could not have been
> active in the dom0, is to blame for the powerdown issue.

Perhaps. If this theory is correct then if you boot baremetal (so no
Xen) and with 'pat=0' on the command line you should see a similar
issue. That is theory.

But it would be really really fantastic if we could confirm that indeed
having those three patches (well, two reverts and one patch) indeed
fix the issue - without you resorting to disabling it altogether.

> 
> I am not sure whether that brings us any further in resolving the
> issue, but it might make sense to involve someone responsibel for
> the Intel IGD driver? Also I could not find much documentation for
> the i915.modeset kernel parameter- probably there's something in
> there that could help?

If you have it set to zero it will make X not work. In effect it should
have the same behavior as if you used the xen-pciback.hide=..
> 
> What are your thoughts on this.

Lets make sure that the patches work for you. If they do then you don't
have to use the work-around (disabling either iommu or not using IGD).
> 
> And as always thanks for your input so far and also thanks in
> advance for your continued help and ideas.
> 
> Am 14.08.13 22:37, schrieb Konrad Rzeszutek Wilk:
> >On Wed, Aug 14, 2013 at 04:34:21PM -0400, Ben Guthro wrote:
> >>This hang looks exactly like this one that I posted about in June:
> >>http://www.gossamer-threads.com/lists/xen/devel/284943?do=post_view_threaded#284943
> >>
> >>This ended up being an interaction with the i915 driver in the kernel, and
> >>pvops use of PAT.
> >>
> >>If you revert the following linux commit:
> >>http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c79c49826270b8b0061b2fca840fc3f013c8a78a
> >
> >And probably also need to revert
> >8eaffa67b43e99ae581622c5133e20b0f48bcef1
> >?
> >>
> >>and then apply:
> >>https://lkml.org/lkml/2012/2/10/229
> >>
> >>You may get good results.
> >>It helped me with a similar problem, at least.
> >>
> >>Ben
> >>
> >>
> >>
> >>On Wed, Aug 14, 2013 at 4:24 PM, Atom2 <ariel.atom2@web2web.at> wrote:
> >>
> >>>Am 14.08.13 22:18, schrieb Andrew Cooper:
> >>>[...]
> >>>
> >>>>
> >>>>Ok thanks.
> >>>>
> >>>>Do you mind confirming whether S5 works with "iommu=off" on the Xen
> >>>>command line?
> >>>>
> >>>>~Andrew
> >>>>
> >>>>  Yes, that works: The system powers off after issuing
> >>>         shutdown -h now
> >>>from the dom0.
> >>>
> >>>
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> >>>
> >
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