[Linaro-acpi] [PATCH v7 04/17] ARM64 / ACPI: Introduce early_param for "acpi" and pass acpi=force to enable ACPI

[Catalin Marinas]

On Wed, Jan 28, 2015 at 05:58:54PM +0000, Timur Tabi wrote:
> On Wed, Jan 14, 2015 at 9:04 AM, Hanjun Guo <hanjun.guo at linaro.org> wrote:
> > From: Al Stone <al.stone at linaro.org>
> >
> > Introduce one early parameters "off" and "force" for "acpi", acpi=off
> > will be the default behavior for ARM64, so introduce acpi=force to
> > enable ACPI on ARM64.
> >
> > Disable ACPI before early parameters parsed, and enable it to pass
> > "acpi=force" if people want use ACPI on ARM64. This ensures DT be
> > the prefer one if ACPI table and DT both are provided at this moment.
> 
> What is the reason to assume that DT is preferred over ACPI?  I would
> have thought that if ACPI is present, then it means we're on an ARM64
> server platform, and therefore it should be used.  It seems silly to
> require acpi=force on every ARM64 server platform.

I'm against requiring acpi=force when *only* ACPI tables are present (I
don't like a command line argument to become firmware-kernel ABI), but
otherwise DT takes precedence (it was the first supported booting method
on arm64 and currently it is more mature and feature-rich than ACPI on
arm64).

-- 
Catalin