linux-kernel - [v12 PATCH 8/8]: POWER: Enable default_idle when power

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Message-ID: <20100415111227.GI16760@linux.vnet.ibm.com>
Date:	Thu, 15 Apr 2010 16:42:27 +0530
From:	Arun R Bharadwaj <arun@...ux.vnet.ibm.com>
To:	peterz@...radead.org
Cc:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Ingo Molnar <mingo@...e.hu>,
	Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
	Dipankar Sarma <dipankar@...ibm.com>,
	Balbir Singh <balbir@...ibm.com>,
	Arun Bharadwaj <arun@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org
Subject: [v12 PATCH 8/8]: POWER: Enable default_idle when power_save=off.

* Arun R Bharadwaj <arun@...ux.vnet.ibm.com> [2010-04-15 16:30:46]:

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 <arun@...ux.vnet.ibm.com>
---
 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
@@ -364,6 +364,8 @@ 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;
+
 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
@@ -167,6 +167,11 @@ static int __init pseries_processor_idle
 	struct cpuidle_subsystem *pseries_subsys = &cpuidle_subsys;
 
 
+	if (boot_option_idle_override) {
+		printk(KERN_DEBUG "Using default idle\n");
+		return 0;
+	}
+
 	result = cpuidle_register_driver(&pseries_idle_driver);
 
 	if (result < 0)
--
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