On 2014-7-29 2:35, Sudeep Holla wrote:

On 24/07/14 14:00, Hanjun Guo wrote:

quoted

From: Al Stone <redacted>

Introduce two early parameters for "acpi", one is the parameter
to disable ACPI on ARM64 and another one is acpi=strict to disable
out-of-spec workarounds.

Reviewed-by: Grant Likely <redacted>
Signed-off-by: Al Stone <redacted>
Signed-off-by: Graeme Gregory <redacted>
Signed-off-by: Hanjun Guo <redacted>
---
  Documentation/kernel-parameters.txt |    3 ++-
  arch/arm64/kernel/acpi.c            |   21 +++++++++++++++++++++
  2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/Documentation/kernel-parameters.txt

b/Documentation/kernel-parameters.txt
index b7fa2f5..d130bd5 100644

--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt

@@ -165,7 +165,7 @@ multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10,

2^20, and 2^30
  bytes respectively. Such letter suffixes can also be entirely omitted.


-    acpi=        [HW,ACPI,X86]
+    acpi=        [HW,ACPI,X86,ARM]
              Advanced Configuration and Power Interface
              Format: { force | off | strict | noirq | rsdt }
              force -- enable ACPI if default was off

@@ -175,6 +175,7 @@ bytes respectively. Such letter suffixes can also be

entirely omitted.
                  strictly ACPI specification compliant.
              rsdt -- prefer RSDT over (default) XSDT
              copy_dsdt -- copy DSDT to memory
+            For ARM64, ONLY "off" and "strict" are available.

              See also Documentation/power/runtime_pm.txt, pci=noacpi

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index c62fce6..ac78e4e 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c

@@ -74,3 +74,24 @@ void __init acpi_boot_table_init(void)
          return;
      }
  }
+
+static int __init parse_acpi(char *arg)
+{
+    if (!arg)
+        return -EINVAL;
+
+    /* "acpi=off" disables both ACPI table parsing and interpreter */
+    if (strcmp(arg, "off") == 0) {
+        disable_acpi();
+    }
+    /* acpi=strict disables out-of-spec workarounds */
+    else if (strcmp(arg, "strict") == 0) {
+        acpi_strict = 1;

This should be default set as I mentioned in patch#1. We can introduce
this option if required in future.

Agreed, Let's keep it strict in the beginning to support ACPI.

Thanks
Hanjun