Loading custom DSDT

[Richard Hughes]

On Tue, 2005-10-25 at 13:17 +0200, Arjan van de Ven wrote:
> On Tue, 2005-10-25 at 12:08 +0100, Richard Hughes wrote:
> > What is the fedora "recommended" way of installing a new ACPI DSDT? Can
> > we make the process of loading a new asl file easier for users in FC5? 
> > 
> > There are lots of broken BIOS's out there that require custom dsdt's, as
> > I've found when debugging power management stuff.
> 
> technically that's a flaw in the linux acpi code; if it doesn't accept
> acpi tables that windows accept then that's a bug.

But some of the ACPI tables out there are *so* broken... The best way to
do this surely is to grab the fixed dsdt from
http://acpi.sourceforge.net/ dump that in /boot, and reboot (I think
this is the way Ubuntu deals with dsdt updates, i.e. build it into the
initrd automatically) and not have to worry about rebuilding a custom
kernel.

I think it's impossible to cope with every broken dsdt table in the
kernel acpi code (looking at some, it's a wonder windows works...) --
but I'm no acpi kernel hacker.

So what do I tell my helpless user? 

1. Start hacking kernel acpi internals, sending patches to lkml that
have kludges for specific laptop models.
2. Rebuild their kernel with the updated dsdt.
3. Email your laptop vendor to release a new bios for a 5 year old
laptop. I'm pretty certain this will be ignored as it "works in
windows".

1,2, and 3 are pretty daunting for a new user. 

There *must* be a better way.

Richard.