* Arun R Bharadwaj [off-list ref] [2009-10-08 15:18:28]:

This patch enables default_idle when power_save=off kernel boot
option is specified.

Earlier, this was done by setting ppc_md.power_save = NULL and hence
HMT_low() and HMT_very_low() was called. Now this is defined under
default_idle() and hence by setting boot_option_idle_override = 1,
the cpuidle registration stuff does not happen and hence default_idle
is chosen in cpuidle_idle_call.

Signed-off-by: Arun R Bharadwaj <redacted>
---
 arch/powerpc/include/asm/processor.h            |    2 ++
 arch/powerpc/kernel/idle.c                      |    4 +++-
 arch/powerpc/platforms/pseries/processor_idle.c |    5 +++++
 3 files changed, 10 insertions(+), 1 deletion(-)

Index: linux.trees.git/arch/powerpc/include/asm/processor.h
===================================================================

--- linux.trees.git.orig/arch/powerpc/include/asm/processor.h
+++ linux.trees.git/arch/powerpc/include/asm/processor.h

@@ -332,6 +332,8 @@ static inline unsigned long get_clean_sp
 }
 #endif
 
+extern int boot_option_idle_override;
+
 #endif /* __KERNEL__ */
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_PROCESSOR_H */

Index: linux.trees.git/arch/powerpc/kernel/idle.c
===================================================================

--- linux.trees.git.orig/arch/powerpc/kernel/idle.c
+++ linux.trees.git/arch/powerpc/kernel/idle.c

@@ -40,9 +40,11 @@
 #define cpu_should_die()	0
 #endif
 
+int boot_option_idle_override = 0;
+
 static int __init powersave_off(char *arg)
 {
-	ppc_md.power_save = NULL;
+	boot_option_idle_override = 1;
 	return 0;
 }
 __setup("powersave=off", powersave_off);

Index: linux.trees.git/arch/powerpc/platforms/pseries/processor_idle.c
===================================================================

--- linux.trees.git.orig/arch/powerpc/platforms/pseries/processor_idle.c
+++ linux.trees.git/arch/powerpc/platforms/pseries/processor_idle.c

@@ -185,6 +185,11 @@ static int __init pseries_processor_idle
 	int cpu;
 	int result;
 
+	if (boot_option_idle_override) {
+		printk(KERN_DEBUG "Using default idle\n");
+		return 0;
+	}
+
 	result = cpuidle_register_driver(&pseries_idle_driver);
 
 	if (result < 0)