Re: 3.0.4 and 3.1-rc4 based dom0 won't boot with acpi=off

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

On Sun, Sep 11, 2011 at 02:44:35AM +0200, Sven Köhler wrote:
> Am 11.09.2011 02:28, schrieb Konrad Rzeszutek Wilk:
> > On Sun, Sep 11, 2011 at 12:43:18AM +0200, Sven Köhler wrote:
> >> Hi,
> >>
> >> when using acpi=off in the kernel or xen command line, the system won't
> >> boot. On real hardware, I saw a few interrupt related warnings from the
> >> usb drivers. The system then seemed to lock up when trying to do I/O via
> >> AHCI. Same in virtualbox. System won't come up.
> > 
> > Not surprised. Without the ACPI we can't find parse the interrupt table,
> > so you don't get any interrupts.
> 
> Thanks for explaining. Now what about the future? Will there be some
> solution for the acpi=off case?

No.
> 
> I'm a bit confused, since your words don't sound like there is a way to
> boot with acpi=off. But other dom0 kernels actually boot with acpi=off.

Sure.
> So after all, some other way for setting up interrupts seems to exist.

The older kernels (XenOLinux) made it possible by copying a lot of the
generic code in its own and making it work. That is not possible with the
upstream kernel.

Well, maybe it is possible, but I am not sure if it is worth the effort.

> 
> > This is result of the reboot issue you have been seeing with your box?
> 
> Yes.
> 
> > You might want to try some parameters on the Xen line to alter how
> > it is suppose to reboot.
> > 
> > /*
> >  * reboot=b[ios] | t[riple] | k[bd] | n[o] [, [w]arm | [c]old]
> 
> Thanks for the list.
> I guess, both reboot=bios and reboot=b is accepted?
> BTW: "no" is missing in the list below. acpi is missing in the list
> above. And actually what's the source for list?

Xen hypervisor source. I just did a quick search for 'reboot='

> (I never find any documentation about the hypervisor options, which is
> pretty frustrating sometimes)
> 
> >  * warm   Don't set the cold reboot flag
> >  * cold   Set the cold reboot flag
> >  * bios   Reboot by jumping through the BIOS (only for X86_32)
> >  * triple Force a triple fault (init)
> >  * kbd    Use the keyboard controller. cold reset (default)
> >  * acpi   Use the RESET_REG in the FADT
> >  */
> 
> So in fact, xen is doing the reboot, and not the dom0 kernel, right?

Yes. Dom0 triggers it though (by invoking an hypercall that tells
Xen to reboot/shutdown the machine).
> (Some people have claimed otherwise)
> 
> Could you imagine to adapt xen's reboot code to the one of linux 3.0
> (which was tweaked quite a lot for maximum compatibility)

I can imagine it.. but without any ideas of why your machine is not rebooting
it is a bit .. difficult.

You could also try on the Xen hypervisor line (Ctlr-A three times) try the 'R'
and see if it does anything.

> 
> 
> 
> Regards,
>   Sven
>