diff options
| author | Baek Kyu, Kim <pocj8ur4in@gmail.com> | 2026-10-31 18:50:39 +0900 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2026-11-02 07:00:05 -0800 |
| commit | f324179e6ccd05dfdc8e98fba2e9d50aea8e7ea2 (patch) | |
| tree | e407d2bf6584fa5f889039b8ee4bcc334745c5c4 | |
| parent | 7cd60538073e465310c94b2a2f0ea8d2f03768ef (diff) | |
hwmon: (gpio-fan) Update the speed cache before dropping the PM reference
set_fan_speed() writes the GPIO control value before dropping the runtime
PM reference when stopping the fan. pm_runtime_put_sync() decrements the
usage count even when suspending the device fails, but the error return
currently leaves speed_index at the previous running speed.
A request for that same running speed then returns success without
changing the GPIOs or taking a runtime PM reference. Retrying the stop
instead drops a reference the driver no longer owns and can trigger a
runtime PM usage count underflow warning.
Update speed_index after writing the GPIOs and before dropping the PM
reference. The initial same-speed check already excludes a stopped fan,
so a zero target is sufficient to identify the transition that needs a
PM put. Preserve the PM error return and the CONFIG_PM=n exception.
This keeps the cached control state and PM reference ownership consistent
without restoring running GPIOs after a possibly partial supply failure.
It does not clear persistent runtime PM errors or claim that a failing
regulator has successfully powered off.
Fixes: 0d01110e6356 ("hwmon: (gpio-fan) Add regulator support")
Cc: stable@vger.kernel.org
Signed-off-by: Baek Kyu, Kim <pocj8ur4in@gmail.com>
Link: https://patch.msgid.link/20261031095039.11683-1-pocj8ur4in@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | drivers/hwmon/gpio-fan.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c index 3f78375eeb44..08b58b49be5b 100644 --- a/drivers/hwmon/gpio-fan.c +++ b/drivers/hwmon/gpio-fan.c @@ -150,7 +150,10 @@ static int set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val); - if (fan_data->speed_index > 0 && speed_index == 0) { + /* The GPIOs have changed, and a PM put drops the reference on error. */ + fan_data->speed_index = speed_index; + + if (speed_index == 0) { int ret; ret = pm_runtime_put_sync(fan_data->dev); @@ -158,8 +161,6 @@ static int set_fan_speed(struct gpio_fan_data *fan_data, int speed_index) return ret; } - fan_data->speed_index = speed_index; - return 0; } |