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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>
This commit is contained in:
Rafael J. Wysocki 2013-06-19 00:45:34 +02:00
parent 6ee22e9d59
commit b9e95fc65e
3 changed files with 36 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/acpi/acpi_lpss.c
View File

@ -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)

20
drivers/acpi/device_pm.c
View File

@ -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;

1
include/acpi/acpi_bus.h
View File

@ -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);