Re: [Fastboot] Fw: Problems with reboot/poweroff on SMP machine

[ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)]

Andrew Morton <akpm-3NddpPZAyC0@public.gmane.org> writes:

> (Added acpi people)
>
> I have a vague feeling that adding local_irq_disable() to acpi_power_off()
> is illegal.

I didn't my preliminary patch just fat fingered that line.
All I was really doing was removing acpi_sleep_prepare(),
to be certain we weren't calling it at the wrong time.


> void acpi_power_off(void)
> {
> 	printk("%s called\n", __FUNCTION__);
> 	local_irq_disable();
> 	acpi_enter_sleep_state(ACPI_STATE_S5);
> }
>
> Can an ACPI person please comment?

>From drivers/acpi/hwsleep.c
> /*******************************************************************************
>  *
>  * FUNCTION:    acpi_enter_sleep_state
>  *
>  * PARAMETERS:  sleep_state         - Which sleep state to enter
>  *
>  * RETURN:      Status
>  *
>  * DESCRIPTION: Enter a system sleep state (see ACPI 2.0 spec p 231)
>  *              THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
>  *
>  ******************************************************************************/
> 
> acpi_status asmlinkage
> acpi_enter_sleep_state (

So at least according to the comments it would be an error
to call that function with interrupts enabled.

So either there is some weird control flow going on that gets
acpi_sleep_prepare called with interrupts disabled.  Or there
is an entirely different problem showing up with acpi_power_off.

My current hunch is some very weird control flow possibly the system
devices not being shutdown in the expected order but I don't know
at the moment.  

I have one bug report that remove the i8259A shutdown fixes
the problem in 2.6.13-rc2.  What I am having a very hard time
seeing is how it could possibly make a difference.

Eric


-------------------------------------------------------
SF.Net email is sponsored by: Discover Easy Linux Migration Strategies
from IBM. Find simple to follow Roadmaps, straightforward articles,
informative Webcasts and more! Get everything you need to get up to
speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click