On 2 Jan 2015, at 09:28, Hanjun Guo [off-list ref] wrote:

quoted

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On 2015?01?02? 04:04, Graeme Gregory wrote:

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On Wed, Dec 31, 2014 at 04:34:46PM +0800, Hanjun Guo wrote:
On 2014?12?31? 04:13, ashwinc at codeaurora.org wrote:
Hi Hanjun,

Overall the document looks good to us. Some minor clarifications below.

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---------- Forwarded message ----------
From: Graeme Gregory <redacted>

Add documentation for the guidelines of how to use ACPI
on ARM64.

Signed-off-by: Graeme Gregory <redacted>
Signed-off-by: Al Stone <redacted>
Signed-off-by: Hanjun Guo <redacted>
---
Documentation/arm64/arm-acpi.txt |  323
++++++++++++++++++++++++++++++++++++++
1 file changed, 323 insertions(+)
create mode 100644 Documentation/arm64/arm-acpi.txt

[..]

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+Relationship with Device Tree
+-----------------------------

[..]

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+When booting using ACPI tables, the /chosen node in DT will still be
parsed
+to extract the kernel command line and initrd path.  No other section of
the
+DT will be used.

Is this still true?

No, we can booting the ACPI system in EFI stub without dtb. Catalin
also pointed out this issue, I will remove this paragraph.

The paragraph is still correct, the /chosen node is always present even
if nothing else is.

Sorry for the confusing, I mean no dtb needed for the command line if
ACPI tables are available.

efi will create a empty dtb if no dtb found, and add the cmd line into
the new created dtb, I'm just wondering, can we remove the limitation
for passing the cmd line in /chosen node in the future?

My point is that on an ACPI based system, we don't really care how EFI_STUB passes
the command line to the rest of the kernel. Since UEFI doesn't need to know about
such detail and since ACPI is only supported with EFI_STUB, we don't need to mention
the chosen node in this document. 

At some point we may even change the way EFI_STUB passes the command line to the 
kernel but this is still irrelevant to ACPI. 

Catalin