From 14796fca2bd22acc73dd0887248d003b0f441d08 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Tue, 18 Jan 2011 20:48:27 -0500 Subject: intel_idle: disable NHM/WSM HW C-state auto-demotion Hardware C-state auto-demotion is a mechanism where the HW overrides the OS C-state request, instead demoting to a shallower state, which is less expensive, but saves less power. Modern Linux should generally get exactly the states it requests. In particular, when a CPU is taken off-line, it must not be demoted, else it can prevent the entire package from reaching deep C-states. https://bugzilla.kernel.org/show_bug.cgi?id=25252 Signed-off-by: Len Brown --- arch/x86/include/asm/msr-index.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch') diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 4d0dfa0d998e..b75eeab2b1ea 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -36,6 +36,10 @@ #define MSR_IA32_PERFCTR1 0x000000c2 #define MSR_FSB_FREQ 0x000000cd +#define MSR_NHM_SNB_PKG_CST_CFG_CTL 0x000000e2 +#define NHM_C3_AUTO_DEMOTE (1UL << 25) +#define NHM_C1_AUTO_DEMOTE (1UL << 26) + #define MSR_MTRRcap 0x000000fe #define MSR_IA32_BBL_CR_CTL 0x00000119 -- cgit v1.2.3 From bfb53ccf1c734b1907df7189eef4c08489827951 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Wed, 16 Feb 2011 01:32:48 -0500 Subject: intel_idle: disable Atom/Lincroft HW C-state auto-demotion 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 --- arch/x86/include/asm/msr-index.h | 1 + drivers/idle/intel_idle.c | 4 ++++ 2 files changed, 5 insertions(+) (limited to 'arch') diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index b75eeab2b1ea..43a18c77676d 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/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 diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 32b25bcaf865..4a5c4a44ffb1 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -345,8 +345,12 @@ 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 */ -- cgit v1.2.3