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SubjectRe: [GIT PULL] x86 setup BIOS workarounds

> + /* ACPI 3.0 added the extended flags support. If bit 0
> + in the extended flags is zero, we're supposed to simply
> + ignore the entry -- a backwards incompatible change! */
> + if (size > 20 && !(buf.ext_flags & 1))
> + continue;


At the risk of rushing to the defense of the ACPI spec...

This does not look like a backwards incompatible change to me.

In ACPI 2.0, size of 20 is always returned, and it would
be a Linux bug if we examined the undefined values after byte 19.

In ACPI 3.0, byte 20 is now defined. So if the BIOS returns
a size >= 21, we are permitted to examine byte 20.

So I agree with the test above, but I do not agree with the comment.

thanks,
Len Brown, Intel Open Source Technology Center



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