path: root/kernel/power
diff options
authorSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>2017-08-15 18:16:59 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-08-18 01:54:22 +0200
commit726fb6b4f2a82a14a906f39bdabac4863b87c01a (patch)
tree9263ffaa63f641d79ad4ff0806ab2b907dfc2c1a /kernel/power
parent23d5855f4774f4f7c246a67057ecacc904696d8a (diff)
ACPI / PM: Check low power idle constraints for debug only
For SoC to achieve its lowest power platform idle state a set of hardware preconditions must be met. These preconditions or constraints can be obtained by issuing a device specific method (_DSM) with function "1". Refer to the document provided in the link below. Here during initialization (from attach() callback of LPS0 device), invoke function 1 to get the device constraints. Each enabled constraint is stored in a table. The devices in this table are used to check whether they were in required minimum state, while entering suspend. This check is done from platform freeze wake() callback, only when /sys/power/pm_debug_messages attribute is non zero. If any constraint is not met and device is ACPI power managed then it prints the device information to kernel logs. Also if debug is enabled in acpi/sleep.c, the constraint table and state of each device on wake is dumped in kernel logs. Since pm_debug_messages_on setting is used as condition to check constraints outside kernel/power/main.c, pm_debug_messages_on is changed to a global variable. Link: http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/power')
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 3074ea4cec0a..3a2ca9066583 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -361,7 +361,7 @@ static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
-static bool pm_debug_messages_on __read_mostly;
+bool pm_debug_messages_on __read_mostly;
static ssize_t pm_debug_messages_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)