Re: Hibernation considerations

From: david
Date: Tue Jul 17 2007 - 17:13:58 EST


On Tue, 17 Jul 2007, Jeremy Maitin-Shepard wrote:

david@xxxxxxx writes:

[snip]

* figure out which devices can wake up
* put devices into low power states (wake-up devices are placed in the Dx
states compatible with the wake capability, the others are powered off)

this can't be done by the image-saving kernel if that kernel doesn't know about
the device.

The image-saving kernel can be made to know about all of the "wake up"
devices; all other devices should have already been powered off by the
"hibernated" kernel.

not nessasarily.

for example, you don't want the "hibernated" kernel to spin down your disks in the general case, but your image-writing kernel may not have drivers in it to talk to some of the disks. when things are powered off this just isn't an issue, but if you use S4 mode instead it is.

David Lang
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