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

On Wed, Jan 28, 2015 at 05:58:54PM +0000, Timur Tabi wrote:

On Wed, Jan 14, 2015 at 9:04 AM, Hanjun Guo [off-list ref] wrote:

quoted

From: Al Stone <redacted>

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).

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