From 991528d7348667924176f3e29addea0675298944 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Mon, 25 Sep 2006 16:28:13 -0700 Subject: ACPI: Processor native C-states using MWAIT Intel processors starting with the Core Duo support support processor native C-state using the MWAIT instruction. Refer: Intel Architecture Software Developer's Manual http://www.intel.com/design/Pentium4/manuals/253668.htm Platform firmware exports the support for Native C-state to OS using ACPI _PDC and _CST methods. Refer: Intel Processor Vendor-Specific ACPI: Interface Specification http://www.intel.com/technology/iapc/acpi/downloads/302223.htm With Processor Native C-state, we use 'MWAIT' instruction on the processor to enter different C-states (C1, C2, C3). We won't use the special IO ports to enter C-state and no SMM mode etc required to enter C-state. Overall this will mean better C-state support. One major advantage of using MWAIT for all C-states is, with this and "treat interrupt as break event" feature of MWAIT, we can now get accurate timing for the time spent in C1, C2, .. states. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Andrew Morton Signed-off-by: Len Brown --- include/acpi/pdc_intel.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'include/acpi/pdc_intel.h') diff --git a/include/acpi/pdc_intel.h b/include/acpi/pdc_intel.h index c5472be6f3a2..e72bfdd887f9 100644 --- a/include/acpi/pdc_intel.h +++ b/include/acpi/pdc_intel.h @@ -13,6 +13,7 @@ #define ACPI_PDC_SMP_C_SWCOORD (0x0040) #define ACPI_PDC_SMP_T_SWCOORD (0x0080) #define ACPI_PDC_C_C1_FFH (0x0100) +#define ACPI_PDC_C_C2C3_FFH (0x0200) #define ACPI_PDC_EST_CAPABILITY_SMP (ACPI_PDC_SMP_C1PT | \ ACPI_PDC_C_C1_HALT | \ @@ -23,8 +24,10 @@ ACPI_PDC_SMP_P_SWCOORD | \ ACPI_PDC_P_FFH) -#define ACPI_PDC_C_CAPABILITY_SMP (ACPI_PDC_SMP_C2C3 | \ - ACPI_PDC_SMP_C1PT | \ - ACPI_PDC_C_C1_HALT) +#define ACPI_PDC_C_CAPABILITY_SMP (ACPI_PDC_SMP_C2C3 | \ + ACPI_PDC_SMP_C1PT | \ + ACPI_PDC_C_C1_HALT | \ + ACPI_PDC_C_C1_FFH | \ + ACPI_PDC_C_C2C3_FFH) #endif /* __PDC_INTEL_H__ */ -- cgit v1.2.3-59-g8ed1b