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ACPI: Processor native C-states using MWAIT

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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 <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Venkatesh Pallipadi
2006-09-25 16:28:13 -07:00
committed by Len Brown
parent b4bd8c6643
commit 991528d734
8 changed files with 242 additions and 56 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
include/acpi/pdc_intel.h
View File

@ -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__ */