| Message ID | 1438080681-3364-1-git-send-email-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Tuesday, July 28, 2015 01:51:21 PM Mika Westerberg wrote: > Commit 20dacb71ad28 ("ACPI / PM: Rework device power management to follow > ACPI 6") changed the device power management to use D3hot if the device > in question does not have _PR3 method even if D3cold was requested by the > caller. > > However, if the device has _PR3 device->power.state is also set to D3hot > instead of D3Cold after power resources have been turned off because > device->power.state will be assigned from "state" instead of > "target_state". > > Next time the device is transitioned to D0, acpi_power_transition() will > find that the current power state of the device is D3hot instead of D3cold > which causes it to power down all resources required for the current > (wrong) state D3hot. > > Below is a simplified ASL example of a real touch panel device which > triggers the problem: > > Scope (TPL1) > { > Name (_PR0, Package (1) { \_SB.PCI0.I2C1.PXTC }) > Name (_PR3, Package (1) { \_SB.PCI0.I2C1.PXTC }) > ... > } > > In both D0 and D3hot the same power resource is required. However, when > acpi_power_transition() turns off power resources required for D3hot (as > the device is transitioned to D0) it powers down PXTC which then makes the > device to lose its power. > > Fix this by assigning "target_state" to the device power state instead of > "state" that is always D3hot even for devices with valid _PR3. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Applied, thanks! Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c index 08dc3ec7e892..337e8118836d 100644 --- a/drivers/acpi/device_pm.c +++ b/drivers/acpi/device_pm.c @@ -231,7 +231,7 @@ int acpi_device_set_power(struct acpi_device *device, int state) dev_warn(&device->dev, "Failed to change power state to %s\n", acpi_power_state_string(state)); } else { - device->power.state = state; + device->power.state = target_state; ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] transitioned to %s\n", device->pnp.bus_id,
Commit 20dacb71ad28 ("ACPI / PM: Rework device power management to follow ACPI 6") changed the device power management to use D3hot if the device in question does not have _PR3 method even if D3cold was requested by the caller. However, if the device has _PR3 device->power.state is also set to D3hot instead of D3Cold after power resources have been turned off because device->power.state will be assigned from "state" instead of "target_state". Next time the device is transitioned to D0, acpi_power_transition() will find that the current power state of the device is D3hot instead of D3cold which causes it to power down all resources required for the current (wrong) state D3hot. Below is a simplified ASL example of a real touch panel device which triggers the problem: Scope (TPL1) { Name (_PR0, Package (1) { \_SB.PCI0.I2C1.PXTC }) Name (_PR3, Package (1) { \_SB.PCI0.I2C1.PXTC }) ... } In both D0 and D3hot the same power resource is required. However, when acpi_power_transition() turns off power resources required for D3hot (as the device is transitioned to D0) it powers down PXTC which then makes the device to lose its power. Fix this by assigning "target_state" to the device power state instead of "state" that is always D3hot even for devices with valid _PR3. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- drivers/acpi/device_pm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)