Re: [linux-pm] Re: Hibernation considerations

On Fri, 20 Jul 2007, Milton Miller wrote:

We can't do this unless we have frozen tasks (this way, or another)
before
carrying out the entire operation.

What can't we do? We've already worked with the drivers to quesce the
hardware and put any information to resume the device in ram. Now we
ask them to put their device in low power mode so we can go to sleep.
Even if we schedule, the only thing userspace could touch is memory.

Userspace can submit I/O requests. Someone will have to audit every
driver to make sure that such I/O requests don't cause a quiesced
device to become active. If the device is active, it will make the
memory snapshot inconsistent with the on-device data.

Alan Stern

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