[lug] ACPI and power off

D. Stimits stimits at comcast.net
Sun Sep 2 15:27:37 MDT 2007

D. Stimits wrote:
> I'm looking at a motherboard that supports BIOS setting of ACPI version
> 1, 2, or 3. Is one more appropriate than another for a modern distro,
> e.g., FC7? I'm asking because I'm trying to get a machine to actually
> power down when told to halt, but under all 3 settings, stock kernel for
> FC7, it is still leaving power on. I'm thinking that a long time ago,
> there was a file in /etc/ that could be set to tell it power off and not
> just halt state. Anyone know what is required for power off to work?
Just a self-reply in case anyone is looking for answers. The system I 
was working on is opteron, which is capable of using both 32 bit and 64 
bit instruction sets, natively. As a result, it's possible to install 
either 32 bit, or 64 bit rpms...and even both if needed. Things like 
unavailable 64 bit drivers can be run instead via 32 bit drivers, 
although performance is not as good under 32 bit. I had to reinstall the 
system due to a desire to change partitioning...during the reinstall I 
did everything the same, except for partitions and not including the 32 
bit rpms in any case where the 64 bit was available. After the install, 
everything just "worked". After having looked at some of the logs, I 
believe there was a conflict between the scripts and binaries that ran 
halt, such that the 32 bit version was not working right...at least not 
when both versions were available. During yum updates, I found quite a 
few update conflicts that were due to 32 bit packages being mixed with 
64. So I guess the moral of the story is that on systems which support 
both 32 and 64 bit natively in hardware, do a thorough cleaning and 
removal of all 32 bit packages when a 64 bit version is also 
installed...yum and rpm dependencies and such are not quite smart enough 
to handle "try 64 bit where possible, and revert to 32 bit where no 64 
bit is available". Once the 32 bit packages (of the ones not needed due 
to 64 bit availability) are gone, everything just runs effortlessly, 
with no configuration issues at all. [As a side note, XP 64 bit could 
not work without providing external drivers...when it comes to 64 bit, 
windows drivers and hardware support is behind those on linux...a 
surprise i had not expected.]

D. Stimits, stimits AT comcast DOT net

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