On Fri, Sep 12, 2014 at 10:00:04PM +0800, Hanjun Guo wrote:
From: Al Stone al.stone@linaro.org
Introduce one early parameters "off" for "acpi" to disable ACPI on ARM64.
This ensures the kernel uses the DT on a platform that provides both ACPI tables and DT.
Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org
Documentation/kernel-parameters.txt | 3 ++- arch/arm64/kernel/acpi.c | 15 +++++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 5ae8608..9dfb1d8 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]
ARM64, not 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 "acpi=off" is available.
Both force and off should be made available, since they're the two main switches here.
See also Documentation/power/runtime_pm.txt, pci=noacpi
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 9252f72..693da7f 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -67,3 +67,18 @@ void __init acpi_boot_table_init(void) if (acpi_table_init()) disable_acpi(); }
+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();
- else
return -EINVAL; /* Core will print when we return error */
For symmetry, you should handle acpi=force here too (i.e. if someone disables by default, which I expect we'll ask for when this code is first merged).
- return 0;
+}
+early_param("acpi", parse_acpi);
1.7.9.5