Re: [PATCH 02/19] ARM64 / ACPI: Introduce early_param for "acpi"

From: Sudeep Holla
Date: Mon Jul 28 2014 - 14:35:26 EST




On 24/07/14 14:00, Hanjun Guo wrote:
From: Al Stone <al.stone@xxxxxxxxxx>

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 <grant.likely@xxxxxxxxxx>
Signed-off-by: Al Stone <al.stone@xxxxxxxxxx>
Signed-off-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
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.

Regards,
Sudeep

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