Re: Question about suspending a system

Johannes Berg
2007-10-15T16:03:59Z

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On Mon, 2007-10-15 at 14:43 +0200, Francis Moreau wrote:

> So my question is that when we suspend the system, it seems that all
> IRQs are masked and I'm a bit suprise since the event that should wake
> up the system is an interrupt. This mask is done by
> arch_suspend_disable_irqs() and none of the arch is overriding this
> stub. If I'm right, how the system should be waked up ?

No, well, in most cases the CPU is actually turned off by some other
chip (like the PMU on powermac systems) and turned on again by it when
the system should wake up.

> Anther point is that the device that consumes a lot on the system is
> the hard drive. I can decrease its power consumption by stopping its
> motor by using "hdparm" but it still consumes too much. So for now I'm
> thinking of stopping to power it up completely. But I don't know it's
> going to be easy to resume the hard drive. Does anybody have another
> idea or have already experience such trick ?

If you search the linuxppc-dev list somebody implemented suspend to ram
(or rather he called it standby) for linkstation powerpc systems. That
might be interesting for you because the CPU is actually not powered off
in that implementatino.

johannes

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