From: Rafael J. Wysocki <rjw@xxxxxxx>
After recent changes of the ACPI device power states definitions, if
power resources are not used for the device's power management, the
state returned by __acpi_bus_get_power() cannot exceed D3hot, because
the return values of _PSC are 0 through 3. However, if the _PR3
method is not present for the device and _PS3 returns 3, we have to
assume that the device is in D3cold, so the value returned by
__acpi_bus_get_power() in that case should be 4.
Similarly, acpi_power_get_inferred_state() should take the power
resources for the D3hot state into account in general, so that it
can return 3 if those resources are "on" or 4 (D3cold) otherwise.
Fix the the above two issues and make sure that if both _PSC and
_PR3 are present for the device, the power resources listed by _PR3
will be used to determine if the number 3 returned by _PSC is meant
to represent D3cold or D3hot.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
drivers/acpi/bus.c | 51 +++++++++++++++++++++++++++++----------------------
drivers/acpi/power.c | 2 +-
2 files changed, 30 insertions(+), 23 deletions(-)
Index: linux/drivers/acpi/bus.c
===================================================================
--- linux.orig/drivers/acpi/bus.c
+++ linux/drivers/acpi/bus.c
@@ -202,37 +202,44 @@ static char *state_string(int state)
static int __acpi_bus_get_power(struct acpi_device *device, int *state)
{
- int result = 0;
- acpi_status status = 0;
- unsigned long long psc = 0;
+ int result = ACPI_STATE_UNKNOWN;
if (!device || !state)
return -EINVAL;
- *state = ACPI_STATE_UNKNOWN;
-
- if (device->flags.power_manageable) {
- /*
- * Get the device's power state either directly (via _PSC) or
- * indirectly (via power resources).
- */
- if (device->power.flags.power_resources) {
- result = acpi_power_get_inferred_state(device, state);
- if (result)
- return result;
- } else if (device->power.flags.explicit_get) {
- status = acpi_evaluate_integer(device->handle, "_PSC",
- NULL, &psc);
- if (ACPI_FAILURE(status))
- return -ENODEV;
- *state = (int)psc;
- }
- } else {
+ if (!device->flags.power_manageable) {
/* TBD: Non-recursive algorithm for walking up hierarchy. */
*state = device->parent ?
device->parent->power.state : ACPI_STATE_D0;
+ goto out;
+ }
+
+ /*
+ * Get the device's power state either directly (via _PSC) or
+ * indirectly (via power resources).
+ */
+ if (device->power.flags.explicit_get) {
+ unsigned long long psc;
+ acpi_status status = acpi_evaluate_integer(device->handle,
+ "_PSC", NULL, &psc);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ result = psc;
+ }
+ /* The test below covers ACPI_STATE_UNKNOWN too. */
+ if (result <= ACPI_STATE_D2) {
+ ; /* Do nothing. */
+ } else if (device->power.flags.power_resources) {
+ int error = acpi_power_get_inferred_state(device, &result);
+ if (error)
+ return error;
+ } else if (result == ACPI_STATE_D3_HOT) {
+ result = ACPI_STATE_D3;
}
+ *state = result;
+ out:
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",
device->pnp.bus_id, state_string(*state)));
Index: linux/drivers/acpi/power.c
===================================================================
--- linux.orig/drivers/acpi/power.c
+++ linux/drivers/acpi/power.c
@@ -631,7 +631,7 @@ int acpi_power_get_inferred_state(struct
* We know a device's inferred power state when all the resources
* required for a given D-state are 'on'.
*/
- for (i = ACPI_STATE_D0; i < ACPI_STATE_D3_HOT; i++) {
+ for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
list = &device->power.states[i].resources;
if (list->count < 1)
continue;
--
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