On Friday, January 10, 2014 03:52:18 PM al.stone@xxxxxxxxxx wrote: > From: Al Stone <al.stone@xxxxxxxxxx> > > Per the ACPI 5.0 specification, section 5.2.9, none of the power > management fields in the FADT are to be used. Short-circuit using > any of those fields in acpi_processor_get_power_info_fadt(). So the spec says that we're supposed to ignore the information in certain FADT fields if the HW_REDUCED_ACPI flag is set. However, what about systems in which that information is actually valid even though HW_REDUCED_ACPI is set? Does it break things if we attempt to use that information? > > Signed-off-by: Al Stone <al.stone@xxxxxxxxxx> > --- > drivers/acpi/processor_idle.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > index eac984a..89f0a0f 100644 > --- a/drivers/acpi/processor_idle.c > +++ b/drivers/acpi/processor_idle.c > @@ -270,6 +270,14 @@ static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr) > if (!pr->pblk) > return -ENODEV; > > + /* > + * Using power management information from the FADT is not > + * allowed when in HW reduced mode. See ACPI 5.0, section > + * 5.2.9. > + */ > + if (acpi_gbl_reduced_hardware) > + return -ENODEV; > + > /* if info is obtained from pblk/fadt, type equals state */ > pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2; > pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3; > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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
