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authorRafael J. Wysocki <rjw@sisk.pl>2011-01-06 23:38:57 +0100
committerLen Brown <len.brown@intel.com>2011-01-12 05:05:39 -0500
commitd0515d9fec68bace144fda57a69f4268fb875209 (patch)
tree5191b7e21adefacc8fdd8c5b45ae1fcdd03a5aa8 /drivers/acpi
parent36237fa0a711c309a38d7a7a9aed727e0eb76449 (diff)
downloadlinux-linaro-android-d0515d9fec68bace144fda57a69f4268fb875209.tar.gz
ACPI / PM: Check status of power resources under mutexes
It certainly is not a good idea to execute _ON or _OFF and _STA for the same power resource at the same time which may happen in some circumstances in theory. To prevent that from happening, read the power state of each power resource under its mutex, as that will prevent the state from being changed at the same time. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/power.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index ac02af419b3..9ac2a9fa90f 100644
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -145,9 +145,8 @@ static int acpi_power_get_state(acpi_handle handle, int *state)
static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
{
- int result = 0, state1;
- u32 i = 0;
-
+ int cur_state;
+ int i = 0;
if (!list || !state)
return -EINVAL;
@@ -155,25 +154,33 @@ static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
/* The state of the list is 'on' IFF all resources are 'on'. */
for (i = 0; i < list->count; i++) {
- /*
- * The state of the power resource can be obtained by
- * using the ACPI handle. In such case it is unnecessary to
- * get the Power resource first and then get its state again.
- */
- result = acpi_power_get_state(list->handles[i], &state1);
+ struct acpi_power_resource *resource;
+ acpi_handle handle = list->handles[i];
+ int result;
+
+ result = acpi_power_get_context(handle, &resource);
if (result)
return result;
- *state = state1;
+ mutex_lock(&resource->resource_lock);
- if (*state != ACPI_POWER_RESOURCE_STATE_ON)
+ result = acpi_power_get_state(handle, &cur_state);
+
+ mutex_unlock(&resource->resource_lock);
+
+ if (result)
+ return result;
+
+ if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
break;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
- *state ? "on" : "off"));
+ cur_state ? "on" : "off"));
- return result;
+ *state = cur_state;
+
+ return 0;
}
static int __acpi_power_on(struct acpi_power_resource *resource)