The devfreq using passive governor is not able to change the governor.
So, the user can not change the governor through 'available_governor' sysfs
entry. Also, the devfreq which don't use the passive governor is not able to
change to 'passive' governor on the fly.
Fixes: 996133119f57 ("PM / devfreq: Add new passive governor")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 34 +++++++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 4bd7a8f71b07..a2c575a5a9ab 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -43,6 +43,11 @@
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);
+static int is_passive_gov(const char *governor_name)
+{
+ return (!strncmp(governor_name, "passive", 7)) ? 1 : 0;
+}
+
/**
* find_device_devfreq() - find devfreq struct using device pointer
* @dev: device pointer used to lookup device devfreq.
@@ -933,6 +938,10 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
if (ret != 1)
return -EINVAL;
+ /* The passive devfreq is not able to change the governor. */
+ if (is_passive_gov(df->governor_name))
+ return 0;
+
mutex_lock(&devfreq_list_lock);
governor = find_devfreq_governor(str_governor);
if (IS_ERR(governor)) {
@@ -972,12 +981,35 @@ static ssize_t available_governors_show(struct device *d,
char *buf)
{
struct devfreq_governor *tmp_governor;
+ struct devfreq *df = to_devfreq(d);
ssize_t count = 0;
mutex_lock(&devfreq_list_lock);
- list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
+
+ /*
+ * The passive devfreq shows only passive governor.
+ * The governor except for passive are not available
+ * for passive devfreq device.
+ */
+ if (is_passive_gov(df->governor_name)) {
+ count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+ "%s ", df->governor_name);
+ goto out;
+ }
+
+ /*
+ * The devfreq device show the registered governor except for
+ * 'passive' governor.
+ */
+ list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
+ if (is_passive_gov(tmp_governor->name))
+ continue;
+
count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
"%s ", tmp_governor->name);
+ }
+
+out:
mutex_unlock(&devfreq_list_lock);
/* Truncate the trailing space */
--
1.9.1
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