acpi interrupt storm when disabling, IPI hang

[Nate Lawson]

Don Bowman wrote:
> When i run 'acpiconf -d', i get an interrupt storm on irq9...
> vmstat -i shows ~1000/s.
> 
> Jun 15 13:41:33 cdata kernel: Interrupt storm detected on "irq9: acpi0";
> throttling interrupt source
> 
> when i try to re-enable, i get an error:
> 
> # acpiconf -e
> acpi0: interrupt handler already installed
>     ACPI-0210: *** Error: Unable to install System Control Interrupt
> Handler, AE_ALREADY_EXISTS
> acpiconf: enable failed: Device not configured
> # 
> 
> System is a Supermicro X5DPE motherboard, dual 2.8GHz Xeon,
> 533MHz FSB, Intel e7501 chipset.

Some systems don't support legacy mode (acpi disabled).  Others support 
legacy mode but don't support transition back to it after acpi has been 
enabled.

In this case, it's likely the flags aren't set right for 
AcpiEnableSubsystem.  I'll look into it.

> The system will not boot 5.x if acpi is disabled.
> It will run 4.x without trouble tho.

What do you mean by "will not boot"?  Hangs?  Panics?  More info is needed.

-Nate