Messages in this thread | | | Date | Wed, 25 Apr 2007 15:55:58 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2: hang in atomic copy) |
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On Thu, 26 Apr 2007, Nigel Cunningham wrote: > > > > And name *one* thing that have in common. > > Set/reset the scsi transaction id thingy? Hibernation didn't work with > SCSI for a long time precisely because that support was missing.
And by "hibernation", you mean what? You mean "snapshot + shutdown", right?
Think about it for five seconds, and then ask yourself: at which point in the "snapshot + shutdown" sequence would you actually tell a disk to shut down?
If you said "snapshot", then you'd be *wrong*.
That's my _point_. The snapshot() function should not (and MUST NOT) tell disks to shut down, because unlike suspend(), we're still going to _use_ those disks afterwards (why? To write out the snapshot image!).
In other words, the act of creating a snapshot has *nothing* to do with suspend.
Now, after you've created (and written out) the snapshot, what do you actually end up doing?
That's right - you end up _shutting down_ the machine, and yes, as part of the _shutdown_ sequence you may actually end up doing a lot of the things that a suspend would do. But that's long *after* you've actually done the "snapshot" part, and has absolutely nothing to do with it.
That's where I started: whole "suspend to disk" thing actually has _more_ to do with "shutdown" than with "suspend".
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