Re: Hibernation considerations

david
2007-07-15T22:27:32Z

On Mon, 16 Jul 2007, Rafael J. Wysocki wrote:

> On Sunday, 15 July 2007 14:58, Dr. David Alan Gilbert wrote:
>> * Rafael J. Wysocki (rjw@sisk.pl) wrote:
>>
>>> (5) Hibernation should be transparent from the applications' point of view
>>>
>>> Generally, applications should not notice that hibernation took place.
>>> [Note that I don't regard all processes as applications and I think that
>>> there may be processes which need to handle the hibernation in a special
>>> way.] Ideally, for example, if some audio is being played when a
>>> hibernation starts, the audio player should be able to continue playing the
>>> same audio after the restore from the point in which it has been
>>> interrupted by the hibernation. Also, the CPU affinities and similar
>>
>> That would be _so_ embarrassing in a library; I'd rather the audio
>> player had the opportunity to consider whether restarting was a good idea.
>>
>>> (6) State of devices from before hibernation should be restored, if possible
>>>
>>> If possible, during a restore devices should be brought back to the same
>>> state in which they were before the corresponding hibernation. Of course
>>> in some situations it might be impossible to do that (eg. the user
>>> connected the hibernated system to a different IP subnet and then
>>> restored), but as a general rule, we should do our best to restore the
>>> state of devices, which is directly related to point (5) above.
>>
>> Or the user unplugs their flash drive after hibernation rather than before.
>>
>> Two things which I think would be nice to consider are:
>> 1) Encryption - I'd actually prefer if my luks device did not
>> remember the key accross a hibernation; I want to be forced to
>> reenter the phrase. However I don't know what the best thing
>> to do to partitions/applications using the luks device is.
>
> Encryption is possible with both the userland hibernation (aka uswsusp) and
> TuxOnIce (formerly known as suspend2). Still, I don't consider it as a "must
> have" feature for a framework to be generally useful (many users don't use it
> anyway).

he's talking about the main system useing an encrypted device/partition,
not the hibernate image being stored encrypted.

This would require the main system 'forget' the keys when it does the
hinbernate and prompt for it again during the wake-up phase.

David Lang