ACPI: Create "idle=halt" bootparam

[pandora-kernel.git] / arch / x86 / kernel / process.c

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 7dceea9..7fc7294 100644 (file)
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -7,6 +7,10 @@
 #include <linux/module.h>
 #include <linux/pm.h>
 #include <linux/clockchips.h>
+#include <asm/system.h>
+
+unsigned long idle_halt;
+EXPORT_SYMBOL(idle_halt);
 
 struct kmem_cache *task_xstate_cachep;
 
@@ -325,7 +329,18 @@ static int __init idle_setup(char *str)
                pm_idle = poll_idle;
        } else if (!strcmp(str, "mwait"))
                force_mwait = 1;
-       else
+       else if (!strcmp(str, "halt")) {
+               /*
+                * When the boot option of idle=halt is added, halt is
+                * forced to be used for CPU idle. In such case CPU C2/C3
+                * won't be used again.
+                * To continue to load the CPU idle driver, don't touch
+                * the boot_option_idle_override.
+                */
+               pm_idle = default_idle;
+               idle_halt = 1;
+               return 0;
+       } else
                return -1;
 
        boot_option_idle_override = 1;