[PATCH 2/2 2.6.37.stable] intel_idle: disable Atom/Lincroft HW C-state auto-demotion

[Len Brown <lenb@kernel.org>]

From: Len Brown <len.brown@intel.com>

upstream bfb53ccf1c734b1907df7189eef4c08489827951

Just as we had to disable auto-demotion for NHM/WSM,
we need to do the same for Atom (Lincroft version).

In particular, auto-demotion will prevent Lincroft
from entering the S0i3 idle power saving state.

https://bugzilla.kernel.org/show_bug.cgi?id=25252

Signed-off-by: Len Brown <len.brown@intel.com>
---
 arch/x86/include/asm/msr-index.h |    1 +
 drivers/idle/intel_idle.c        |    4 ++++
 2 files changed, 5 insertions(+), 0 deletions(-)

Index: linux-2.6.37.y/arch/x86/include/asm/msr-index.h
===================================================================
--- linux-2.6.37.y.orig/arch/x86/include/asm/msr-index.h
+++ linux-2.6.37.y/arch/x86/include/asm/msr-index.h
@@ -39,6 +39,7 @@
 #define MSR_NHM_SNB_PKG_CST_CFG_CTL	0x000000e2
 #define NHM_C3_AUTO_DEMOTE		(1UL << 25)
 #define NHM_C1_AUTO_DEMOTE		(1UL << 26)
+#define ATM_LNC_C6_AUTO_DEMOTE		(1UL << 25)
 
 #define MSR_MTRRcap			0x000000fe
 #define MSR_IA32_BBL_CR_CTL		0x00000119
Index: linux-2.6.37.y/drivers/idle/intel_idle.c
===================================================================
--- linux-2.6.37.y.orig/drivers/idle/intel_idle.c
+++ linux-2.6.37.y/drivers/idle/intel_idle.c
@@ -340,8 +340,12 @@ static int intel_idle_probe(void)
 		break;
 
 	case 0x1C:	/* 28 - Atom Processor */
+		cpuidle_state_table = atom_cstates;
+		break;
+
 	case 0x26:	/* 38 - Lincroft Atom Processor */
 		cpuidle_state_table = atom_cstates;
+		auto_demotion_disable_flags = ATM_LNC_C6_AUTO_DEMOTE;
 		break;
 
 	case 0x2A:	/* SNB */