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ACPI: Enable bit 11 in _PDC to advertise hw coord
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Bit 11 in intel PDC definitions is meant for OS capability to handle
hardware coordination of P-states. In Linux we have always supported
hwardware coordination of P-states. Just let the BIOSes know that we
support it, by setting this bit.

Some BIOSes use this bit to choose between hardware or software coordination
and without this change below, BIOSes switch to software coordination, which
is not very optimal in terms of power consumption and extra wakeups from idle.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
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Pallipadi, Venkatesh authored and Len Brown committed Feb 7, 2009
1 parent db1461a commit d96f94c
Showing 1 changed file with 2 additions and 0 deletions.
2 changes: 2 additions & 0 deletions include/acpi/pdc_intel.h
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@
#define ACPI_PDC_SMP_T_SWCOORD (0x0080)
#define ACPI_PDC_C_C1_FFH (0x0100)
#define ACPI_PDC_C_C2C3_FFH (0x0200)
#define ACPI_PDC_SMP_P_HWCOORD (0x0800)

#define ACPI_PDC_EST_CAPABILITY_SMP (ACPI_PDC_SMP_C1PT | \
ACPI_PDC_C_C1_HALT | \
Expand All @@ -22,6 +23,7 @@
#define ACPI_PDC_EST_CAPABILITY_SWSMP (ACPI_PDC_SMP_C1PT | \
ACPI_PDC_C_C1_HALT | \
ACPI_PDC_SMP_P_SWCOORD | \
ACPI_PDC_SMP_P_HWCOORD | \
ACPI_PDC_P_FFH)

#define ACPI_PDC_C_CAPABILITY_SMP (ACPI_PDC_SMP_C2C3 | \
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