Re: [linux-pm] pm loss development

[Raffaele Recalcati]

On Sat, May 14, 2011 at 8:53 PM, Oliver Neukum <oliver@xxxxxxxxxx> wrote:
> Am Donnerstag, 12. Mai 2011, 21:27:44 schrieb Rafael J. Wysocki:
>> On Thursday, May 12, 2011, Raffaele Recalcati wrote:
>> > What happen normally in runtime pm implementation is that every devices
>> > are switched off and are enabled only when needed.
>> > In our case instead we have a completely functional embedded system and,
>> > when an asyncrhonous event appear, we have only some tens milliseconds
>> > before the actual power failure takes place.
>> > This patchset add a support in order to switch off not vital part of the system,
>> > in order to allow the board to survive longer.
>> > This allow the possibility to save important data.
>>
>> OK, so first, who decides what parts of the system are vital and what aren't?
>
> If you know that power is failing in a few miliseconds, only stuff that can lead to data
> corruption is vital. In that timeframe you can't even flush buffers.

Remember that if you switch off some peripherals this timeframe
becomes longer, so maybe you have enough time to sync some storage
devices.

Bye,
Raffaele
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