Re: [PATCH] ACPI: Implement overriding of arbitrary ACPI tables via initrd

["H. Peter Anvin" <hpa@zytor.com>]

On 03/25/2012 05:45 PM, Thomas Renninger wrote:
> Best would be if no distro specific mkinitrd magic is needed and it's
> just as easy as it is:
> cp DSDT.aml /boot/initrd-test
> cat /boot/initrd >>/boot/initrd-test
> and add a test boot entry to grub's menu.lst or whereever.
> Then developers would not have to look at distro specific implementations
> (which should not exist) about how to test a table quickly.

There is no distro-specific magic needed.  What I'm proposing is
basically what you have above, except that your DSDT.aml would be
wrapped in a cpio header.  What I would like to ask from you is if it
makes sense to have kernel/acpi/DSDT, kernel/acpi/SSDT and so on, or
just make it a single kernel/acpi member.

By wrapping in a cpio container it becomes a generic mechanism.

>> By the way, if "relying on the bootloader" was an option in any way
> 
> Why exactly is a change in the bootloader not an option?
> Not sure whether a version number is passed, but the magic number could be
> changed for now.

There are a lot of bootloaders, and one of the most commonly used ones
has a very adversarial relationship with the kernel maintainers.

> If the new magic number is passed, we get a linked list.

The linked list stuff is already supported.  This interface has been
supported in the kernel since 2007.

	-hpa