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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-12-13 09:56:13 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-12-27 11:02:08 +0100
commit75a80267410e38ab76c4ceb39753f96d72113781 (patch)
tree08c172e0d40ae21128686957ec078065ef4bc1d0 /drivers/cpuidle
parentintel_idle: Use ACPI _CST for processor models without C-state tables (diff)
downloadlinux-75a80267410e38ab76c4ceb39753f96d72113781.tar.xz
linux-75a80267410e38ab76c4ceb39753f96d72113781.zip
cpuidle: Allow idle states to be disabled by default
In certain situations it may be useful to prevent some idle states from being used by default while allowing user space to enable them later on. For this purpose, introduce a new state flag, CPUIDLE_FLAG_OFF, to mark idle states that should be disabled by default, make the core set CPUIDLE_STATE_DISABLED_BY_USER for those states at the initialization time and add a new state attribute in sysfs, "default_status", to inform user space of the initial status of the given idle state ("disabled" if CPUIDLE_FLAG_OFF is set for it, "enabled" otherwise). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/cpuidle.c6
-rw-r--r--drivers/cpuidle/sysfs.c10
2 files changed, 15 insertions, 1 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 33d19c8eb027..a2af7bb8f0a5 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -572,10 +572,14 @@ static int __cpuidle_register_device(struct cpuidle_device *dev)
if (!try_module_get(drv->owner))
return -EINVAL;
- for (i = 0; i < drv->state_count; i++)
+ for (i = 0; i < drv->state_count; i++) {
if (drv->states[i].flags & CPUIDLE_FLAG_UNUSABLE)
dev->states_usage[i].disable |= CPUIDLE_STATE_DISABLED_BY_DRIVER;
+ if (drv->states[i].flags & CPUIDLE_FLAG_OFF)
+ dev->states_usage[i].disable |= CPUIDLE_STATE_DISABLED_BY_USER;
+ }
+
per_cpu(cpuidle_devices, dev->cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 38ef770be90d..254d1560dc19 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -327,6 +327,14 @@ static ssize_t store_state_disable(struct cpuidle_state *state,
return size;
}
+static ssize_t show_state_default_status(struct cpuidle_state *state,
+ struct cpuidle_state_usage *state_usage,
+ char *buf)
+{
+ return sprintf(buf, "%s\n",
+ state->flags & CPUIDLE_FLAG_OFF ? "disabled" : "enabled");
+}
+
define_one_state_ro(name, show_state_name);
define_one_state_ro(desc, show_state_desc);
define_one_state_ro(latency, show_state_exit_latency);
@@ -337,6 +345,7 @@ define_one_state_ro(time, show_state_time);
define_one_state_rw(disable, show_state_disable, store_state_disable);
define_one_state_ro(above, show_state_above);
define_one_state_ro(below, show_state_below);
+define_one_state_ro(default_status, show_state_default_status);
static struct attribute *cpuidle_state_default_attrs[] = {
&attr_name.attr,
@@ -349,6 +358,7 @@ static struct attribute *cpuidle_state_default_attrs[] = {
&attr_disable.attr,
&attr_above.attr,
&attr_below.attr,
+ &attr_default_status.attr,
NULL
};