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>
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 652fd5c..cab13f2 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -164,15 +164,24 @@
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)