[ALUG] R31 Sleep...Can We Resolve This

Wayne Stallwood ALUGlist at digimatic.co.uk
Sat Jan 15 19:37:17 GMT 2011


On 15/01/11 11:14, Simon Royal wrote:

> I find it odd that my 10 year old G3 500Mhz Mac can come back from
> sleep within seconds but my sons 2.2Ghz P4 laptop takes about 20
> seconds to get back.
> >
> I had a ThinkPad 600 and 240x about a year ago and they just worked
> with sleep. Open the lid and it comes back on, sometimes faced with a
> log back in screen but it worked.
>
> So why can I not get this R31 to behave in a similar way? Why would a
> 600 and 240x have better power down support than this R31?
>
> If I press Fn+F4 it will go to sleep, but then coming back on takes a
> boot (bios splash, grub etc) and then you get the log back in screen.
>


It sounds like you are comparing suspend and hibernate. Using Hibernate 
on the R31 and your Son's machine and suspend on the Mac

Suspend keeps the memory contents in the memory which remains powered 
with the machine in a low power state (usually shown by a pulsing power 
light)

Resuming from this is pretty much instant because all the machine has to 
do is reinitialise the hardware a bit and of it goes. The downside is 
there is a finite time you can remain in suspend because it still drains 
the battery a bit and when the battery is completely discharged the 
suspended state is lost.

Hibernate writes the contents of memory out to a hibernation file (or in 
the case of Linux just to the swap partition) and powers the machine 
down completely. Then on power up this gets written back into RAM from 
disk. This takes longer (depending on the speed of your disk and how 
much physical ram you have) but has the advantage that the machine is to 
all intents and purposes fully powered off so you can remain in this 
state indefinitely.

Linux supports both states, but may only support one of them on your 
specific hardware so you may have to experiment. The fact that you are 
seeing a Bios POST screen usually signifies that you are in the 
Hibernate state not Suspend at the moment. You can change what happens 
when you close the lid in the power management settings, see if there is 
the option to suspend rather than hibernate there and give it a go.




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