I mentioned APM because it seemed the simplest. Realisticaly you'd want to follow the LinuxBIOS approach and do minimal stuff at the BIOS level and move most of the information to a linux driver. So really all the BIOS portion has to detect and support are the conditions where the CPU goes through reset. This should only be the suspend to ram and the suspend to disk states.
So how about a new simple LinuxBIOS PM interface?
Jordan
At 05:18 PM 11/26/2003 +0100, Stefan Reinauer wrote:
- jarcher@pobox.com jarcher@pobox.com [031126 16:32]:
I'll raise the question to the next level....
Has there been any discussion of putting any power management support into the LinuxBIOS. I've got a possible need for some basics, like suspend to RAM. Classic APM might be enough and simple to implement. ACPI would
be a
good choice, but I'm not sure about how much ROM foot print would be
needed.
Since ACPI is, similar to FCode, an interface based on abstracted binary code, it would probably be easier to add ACPI support to LinuxBIOS than supporting APM which needs code hooks.
The ACPI tables could be a) generated by or b) stored in LinuxBIOS as is and will be found and interpreted by the Linux Kernel. But besides the technical issues there's also a legal question when including ACPI tables (some are patented by MS and not freely usable iirc, others might be copyrighted by Awkward & Co.) There are also kernel patches for Linux that allow attaching some of the ACPI tables to an initial ramdisk. This can be used to override broken bios ACPI tables with corrected ones without reflashing the bios.
Stefan
-- Stefan Reinauer, SUSE LINUX AG Teamleader Architecture Development