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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-06-19 00:45:34 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-06-20 00:49:06 +0200
commitb9e95fc65ededbec083aa91b4faa58ad992c0891 (patch)
tree9f2b2867d14e6ad7b6a3cef1a2a776518ae83517
parent6ee22e9d59151550a55d370b14109bdae8b58bda (diff)
downloadlinux-linaro-stable-b9e95fc65ededbec083aa91b4faa58ad992c0891.tar.gz
ACPI / LPSS: Power up LPSS devices during enumeration
Commit 7cd8407 (ACPI / PM: Do not execute _PS0 for devices without _PSC during initialization) introduced a regression on some systems with Intel Lynxpoint Low-Power Subsystem (LPSS) where some devices need to be powered up during initialization, but their device objects in the ACPI namespace have _PS0 and _PS3 only (without _PSC or power resources). To work around this problem, make the ACPI LPSS driver power up devices it knows about by using a new helper function acpi_device_fix_up_power() that does all of the necessary sanity checks and calls acpi_dev_pm_explicit_set() to put the device into D0. Reported-and-tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/acpi/acpi_lpss.c21
-rw-r--r--drivers/acpi/device_pm.c20
-rw-r--r--include/acpi/acpi_bus.h1
3 files changed, 36 insertions, 6 deletions
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 652fd5ce303c..cab13f2fc28e 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -164,15 +164,24 @@ static int acpi_lpss_create_device(struct acpi_device *adev,
if (dev_desc->clk_required) {
ret = register_device_clock(adev, pdata);
if (ret) {
- /*
- * Skip the device, but don't terminate the namespace
- * scan.
- */
- kfree(pdata);
- return 0;
+ /* Skip the device, but continue the namespace scan. */
+ ret = 0;
+ goto err_out;
}
}
+ /*
+ * This works around a known issue in ACPI tables where LPSS devices
+ * have _PS0 and _PS3 without _PSC (and no power resources), so
+ * acpi_bus_init_power() will assume that the BIOS has put them into D0.
+ */
+ ret = acpi_device_fix_up_power(adev);
+ if (ret) {
+ /* Skip the device, but continue the namespace scan. */
+ ret = 0;
+ goto err_out;
+ }
+
adev->driver_data = pdata;
ret = acpi_create_platform_device(adev, id);
if (ret > 0)
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 318fa32a141e..31c217a42839 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -290,6 +290,26 @@ int acpi_bus_init_power(struct acpi_device *device)
return 0;
}
+/**
+ * acpi_device_fix_up_power - Force device with missing _PSC into D0.
+ * @device: Device object whose power state is to be fixed up.
+ *
+ * Devices without power resources and _PSC, but having _PS0 and _PS3 defined,
+ * are assumed to be put into D0 by the BIOS. However, in some cases that may
+ * not be the case and this function should be used then.
+ */
+int acpi_device_fix_up_power(struct acpi_device *device)
+{
+ int ret = 0;
+
+ if (!device->power.flags.power_resources
+ && !device->power.flags.explicit_get
+ && device->power.state == ACPI_STATE_D0)
+ ret = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);
+
+ return ret;
+}
+
int acpi_bus_update_power(acpi_handle handle, int *state_p)
{
struct acpi_device *device;
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 636c59f2003a..c13c919ab99e 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -382,6 +382,7 @@ const char *acpi_power_state_string(int state);
int acpi_device_get_power(struct acpi_device *device, int *state);
int acpi_device_set_power(struct acpi_device *device, int state);
int acpi_bus_init_power(struct acpi_device *device);
+int acpi_device_fix_up_power(struct acpi_device *device);
int acpi_bus_update_power(acpi_handle handle, int *state_p);
bool acpi_bus_power_manageable(acpi_handle handle);