[PATCH 1/3] PM / devfreq: Fix available_governor sysfs
From: Chanwoo Choi <cw00.choi@samsung.com>
Date: 2017-01-18 06:56:58
Also in:
lkml, stable
Subsystem:
device frequency (devfreq), the rest · Maintainers:
MyungJoo Ham, Kyungmin Park, Chanwoo Choi, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2017-01-24 · Re: [PATCH 1/3] PM / devfreq: Fix available_governor sysfs · Chanwoo Choi <cw00.choi@samsung.com>
- 2017-01-24 · RE: [PATCH 1/3] PM / devfreq: Fix available_governor sysfs · MyungJoo Ham <myungjoo.ham@samsung.com>
- 2017-01-24 · RE: [PATCH 1/3] PM / devfreq: Fix available_governor sysfs · MyungJoo Ham <myungjoo.ham@samsung.com>
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@vger.kernel.org
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
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