[ltp] Power Saving Modes (was Problem with Acpi)

[Michael Perry]

On Thu, 7 Oct 2004 15:18:43 +0100, Steve Harris
<s.w.harris@ecs.soton.ac.uk> wrote:
> On Thu, Oct 07, 2004 at 09:14:12 -0500, Jay Strauss wrote:
> > Hi,
> >
> > Being new to Linux on my thinkpad, I read the above thread, then read
> > the web for a while.  I got the impression that you can suspend and/or
> > hibernate.  One where stuff stays in RAM (but uses less power than
> > normal??) and one where your active RAM get stored down to disk before
> > you power off.
> >
> > Are both of these types available on Linux?
> 
> Yes, though one takes more work than the other.
> > What are the proper names for the different type of power saving modes?
> 
> Idunno what the proper names are, but in linux they are generally referred
> to as "Suspend to RAM" and "Suspend to disk".
> 
> - Steve
> 
> 
> --
> The linux-thinkpad mailing list home page is at:
> http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad
> 

One of the things I found with an IBM Thinkpad T23; granted an older
model...  But with a very new BIOS was that the kernel based ACPI
simply would not work.  I had to download the latest ACPI patches from
acpi.sf.net and patch the kernel to make ACPI truly work.  Once I did
that, ACPI worked perfectly but then for some reason softwaresuspend2
would not be patched to the kernel no matter what I tried.  In the
archives of the list, there are a number of posts that I can find in
my gmail account which describes some of the work arounds suggested. 
There appears to be an order to things with a 2.6.8.1 kernel to get it
all happy.  I ended up first patching with the softwaresuspend2
patches, then the latest ACPI patches and then compiling.  I am
running on debian unstable here.

Another thing I found is that some of my kernel modules would not
allow my laptop to suspend if I use acpi to send the event.  I had to
unload linuxant's driverloader module first or the laptop would
prepare to suspend; but nothing ever happened.

Without the latest acpi patches, every time the laptop woke up, it was
to a kernel panic.

-- 
Michael Perry
meperry@gmail.com