Jeff Garzik <[EMAIL PROTECTED]> writes: > "Eric W. Biederman" wrote: > > > > O.k. I just looked at how the linux kernel is using acpi, > > in acpitable.c and reskimmed the acpi spec to see what I was > > missing. > > > > The Linux kernel isn't using true acpi at that point. All > > it has is code for the mptables, and it finds the mptable > > (or a minor variation of thereof via acpi). But acpi > > as a side issue does provide a good way to find other > > tables which is handy. It looks like it may also provide > > hooks to point at the more interesting dmi tables. > > > > The stuff isn't strictly acpi but it is very useful. > > How feasible/reasonable would it be to have linuxbios use ACPI as its > table format?
We could embbed an acpi table in the LinuxBIOS table. Or provide a converter. For now I like the idea of at least having an internal format we can control and then converting on the fly to what the OS needs. When I checked the core of ACPI had some rather strong PC architecture assumptions that I wouldn't want to get caught with. And to use it fully you have to do the AML thing, which is ugly. > The ACPI guys seem the listen and respond to feedback, they might even > consider changes to drivers/acpi for linuxbios, if the changes were > generally useful. The ACPI linux developers? Hopefully we can just be another table format that gets parsed. > And, slight tangent, the general ia32 OS kernel method for probing > memory size(s) is via BIOS INT e820 (or is it e802?). int 0x15 eax = e820 gives the ranges int 0x15 eax = e801 gives the top of memory not limited to 64M int 0x15 ax=88 gives the amount of extended memory. > Anyway, it > provides a list of memory ranges, and what type of information that > memory range contains (useable RAM, ACPI table, etc.). Providing e820 > info to ia32 OS kernels would be a big step towards providing an easy > way to serve memory info and ACPI tables to all OS's. We already provide e820 style information, in the LinuxBIOS table, which sits just below address 0. I might relocate it someday with a pointer but that just seems silly. So we are pretty flexible, and ultimately the output can be whatever is sane. Eric
