On 2 Jan 2015, at 09:28, Hanjun Guo <hanjun.guo@xxxxxxxxxx> wrote: >>> On 2015年01月02日 04:04, Graeme Gregory wrote: >>>> On Wed, Dec 31, 2014 at 04:34:46PM +0800, Hanjun Guo wrote: >>>> On 2014年12月31日 04:13, ashwinc@xxxxxxxxxxxxxx wrote: >>>> Hi Hanjun, >>>> >>>> Overall the document looks good to us. Some minor clarifications below. >>>> >>>>> ---------- Forwarded message ---------- >>>>> From: Graeme Gregory <graeme.gregory@xxxxxxxxxx> >>>>> >>>>> Add documentation for the guidelines of how to use ACPI >>>>> on ARM64. >>>>> >>>>> Signed-off-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx> >>>>> Signed-off-by: Al Stone <al.stone@xxxxxxxxxx> >>>>> Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx> >>>>> --- >>>>> Documentation/arm64/arm-acpi.txt | 323 >>>>> ++++++++++++++++++++++++++++++++++++++ >>>>> 1 file changed, 323 insertions(+) >>>>> create mode 100644 Documentation/arm64/arm-acpi.txt >>>> >>>> [..] >>>> >>>>> +Relationship with Device Tree >>>>> +----------------------------- >>>> >>>> [..] >>>> >>>>> +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 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
