On Mon, Sep 1, 2014 at 8:57 AM, Hanjun Guo hanjun.guo@linaro.org wrote:
From: Al Stone al.stone@linaro.org
Introduce one early parameters "off" for "acpi" to disable ACPI on ARM64.
It might be worth mentioning the purpose of this in the changelog (and maybe the documentation). I don't think this parameter is supported on ia64, and on x86 it seems like it's mostly used as a "fix" by Ubuntu users who consider the problem resolved when they find this parameter. That just means we don't get a chance to fix the real underlying problem, so I'm not sure it's a real benefit to have the parameter.
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] 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. See also Documentation/power/runtime_pm.txt, pci=noacpidiff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index b6940a0..9547275 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -74,3 +74,18 @@ void __init acpi_boot_table_init(void)
- TBD when ARM/ARM64 starts to support suspend...
*/ int (*acpi_suspend_lowlevel)(void) = NULL;
+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();elsereturn -EINVAL; /* Core will print when we return error */return 0;+}
+early_param("acpi", parse_acpi);
1.7.9.5