On Mon, Feb 02 2009, Pallipadi, Venkatesh wrote: > > 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. I can confirm that this fixes the excessive reschedule ipi count on an x60 with the ondemand governor. Can we please get this into 2.6.29? > > Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx> > > --- > include/acpi/pdc_intel.h | 2 ++ > 1 file changed, 2 insertions(+) > > Index: linux-2.6/include/acpi/pdc_intel.h > =================================================================== > --- linux-2.6.orig/include/acpi/pdc_intel.h 2009-01-20 16:11:20.000000000 -0800 > +++ linux-2.6/include/acpi/pdc_intel.h 2009-02-02 10:32:06.000000000 -0800 > @@ -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 | \ > @@ -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 | \ -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
