Re: potential pitfall? changing configuration while PC in hibernate

Alan Stern
2005-03-21T15:29:29Z

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On Mon, 21 Mar 2005, Arioch wrote:

> AS: where it counts, by hibernate i mean Suspend-to-disk, not
> suspend-to-RAM.
>
> I wonder, if hardware configuration asked for changes when resuming from
> hibernate ?
>
> I have a notebook with USB1 keyboard-and-hub (Cherry) and an USB2 Flash
> drive.
>
> Keyboard reports it can give 100 mA of current per-port.
> USB disk reports it consumes 200 mA.
>
> So de jure this disk is not to be turned on, or at least Linux is to ask
> user if he wants to run this device, even he understands it is risky.
> Ok, this question is not for Power-Management forum.
>
> But i remember a couple of pitfalls i met on Windows and do not want to
> see them in Linux.
>
> When i plug this USB dirve into keyboard when Win2003 is running,
> Windows rejects the device since it requests too much power.
> But if i put Windows to hibernate, then plug the USB Drive and then
> resume Windows - it forgets to check for power requirements and tunrs
> device on (which is useful, but which is a bug :-) )
>
> So i wonder if there are (planned) some measures to test for hardware
> changes, why PC was hibernated.

This specific case -- plugging in a new USB device while the system is
asleep -- will be handled correctly. In fact, it will be handled exactly
the same as if you had plugged in the device after waking up the system.

Alan Stern