From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
If the PNP0D80 device is present and its _DSM appears to be valid,
there is no reason to avoid using it even if ACPI_FADT_LOW_POWER_S0
is unset in the FADT, because suspend-to-idle may be the only way to
suspend the system if S3 is not supported by the platform, so do not
return early from lps0_device_attach() in that case.
However, still check ACPI_FADT_LOW_POWER_S0 when deciding whether or
not suspend-to-idle should be the default system suspend method.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/acpi/x86/s2idle.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
Index: linux-pm/drivers/acpi/x86/s2idle.c
===================================================================
--- linux-pm.orig/drivers/acpi/x86/s2idle.c
+++ linux-pm/drivers/acpi/x86/s2idle.c
@@ -369,9 +369,6 @@ static int lps0_device_attach(struct acp
if (lps0_device_handle)
return 0;
- if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
- return 0;
-
if (acpi_s2idle_vendor_amd()) {
/* AMD0004, AMD0005, AMDI0005:
* - Should use rev_id 0x0
@@ -421,10 +418,12 @@ static int lps0_device_attach(struct acp
lpi_device_get_constraints();
/*
- * Use suspend-to-idle by default if the default suspend mode was not
- * set from the command line.
+ * Use suspend-to-idle by default if ACPI_FADT_LOW_POWER_S0 is set in
+ * the FADT and the default suspend mode was not set from the command
+ * line.
*/
- if (mem_sleep_default > PM_SUSPEND_MEM && !acpi_sleep_default_s3)
+ if ((acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0) &&
+ mem_sleep_default > PM_SUSPEND_MEM && !acpi_sleep_default_s3)
mem_sleep_current = PM_SUSPEND_TO_IDLE;
/*
