| Message ID | 20200524025117.15679-1-dinghao.liu@zju.edu.cn (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: magnetometer: ak8974: Fix runtime PM imbalance on error | expand |
On Sun, May 24, 2020 at 4:51 AM Dinghao Liu <dinghao.liu@zju.edu.cn> wrote: > When devm_regmap_init_i2c() returns an error code, a pairing > runtime PM usage counter decrement is needed to keep the > counter balanced. For error paths after ak8974_set_power(), > ak8974_detect() and ak8974_reset(), things are the same. > > However, When iio_triggered_buffer_setup() returns an error > code, we don't need such a decrement because there is already > one before this call. Things are the same for other error paths > after it. > > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config); > if (IS_ERR(ak8974->map)) { > dev_err(&i2c->dev, "failed to allocate register map\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev); > return PTR_ERR(ak8974->map); This is correct. > ret = ak8974_set_power(ak8974, AK8974_PWR_ON); > if (ret) { > dev_err(&i2c->dev, "could not power on\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev); > goto power_off; What about just changing this to goto disable_pm; > ret = ak8974_detect(ak8974); > if (ret) { > dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev); > goto power_off; goto disable_pm; > @@ -786,6 +792,8 @@ static int ak8974_probe(struct i2c_client *i2c, > ret = ak8974_reset(ak8974); > if (ret) { > dev_err(&i2c->dev, "AK8974 reset failed\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev); goto disable_pm; > disable_pm: > - pm_runtime_put_noidle(&i2c->dev); > pm_runtime_disable(&i2c->dev); > ak8974_set_power(ak8974, AK8974_PWR_OFF); Keep the top pm_runtime_put_noidle(). The ak8974_set_power() call is fine, the power on call does not need to happen in balance. Sure it will attempt to write a register but so will the power on call. Yours, Linus Walleij
Hi, Linus > On Sun, May 24, 2020 at 4:51 AM Dinghao Liu <dinghao.liu@zju.edu.cn> wrote: > > > When devm_regmap_init_i2c() returns an error code, a pairing > > runtime PM usage counter decrement is needed to keep the > > counter balanced. For error paths after ak8974_set_power(), > > ak8974_detect() and ak8974_reset(), things are the same. > > > > However, When iio_triggered_buffer_setup() returns an error > > code, we don't need such a decrement because there is already > > one before this call. Things are the same for other error paths > > after it. > > > > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > > > ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config); > > if (IS_ERR(ak8974->map)) { > > dev_err(&i2c->dev, "failed to allocate register map\n"); > > + pm_runtime_put_noidle(&i2c->dev); > > + pm_runtime_disable(&i2c->dev); > > return PTR_ERR(ak8974->map); > > This is correct. > > > ret = ak8974_set_power(ak8974, AK8974_PWR_ON); > > if (ret) { > > dev_err(&i2c->dev, "could not power on\n"); > > + pm_runtime_put_noidle(&i2c->dev); > > + pm_runtime_disable(&i2c->dev); > > goto power_off; > > What about just changing this to goto disable_pm; > > > ret = ak8974_detect(ak8974); > > if (ret) { > > dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n"); > > + pm_runtime_put_noidle(&i2c->dev); > > + pm_runtime_disable(&i2c->dev); > > goto power_off; > > goto disable_pm; > > > @@ -786,6 +792,8 @@ static int ak8974_probe(struct i2c_client *i2c, > > ret = ak8974_reset(ak8974); > > if (ret) { > > dev_err(&i2c->dev, "AK8974 reset failed\n"); > > + pm_runtime_put_noidle(&i2c->dev); > > + pm_runtime_disable(&i2c->dev); > > goto disable_pm; > > > disable_pm: > > - pm_runtime_put_noidle(&i2c->dev); > > pm_runtime_disable(&i2c->dev); > > ak8974_set_power(ak8974, AK8974_PWR_OFF); > > Keep the top pm_runtime_put_noidle(). I found that there was already a pm_runtime_put() before iio_triggered_buffer_setup() (just after pm_runtime_use_autosuspend). So if we keep the pm_runtime_put_noidle() here, we will have two pmusage counter decrement. Do you think this is a bug? Regards, Dinghao > > The ak8974_set_power() call is fine, the power on call does not > need to happen in balance. Sure it will attempt to write a register > but so will the power on call. > > Yours, > Linus Walleij
On Tue, May 26, 2020 at 7:14 AM <dinghao.liu@zju.edu.cn> wrote: > > On Sun, May 24, 2020 at 4:51 AM Dinghao Liu <dinghao.liu@zju.edu.cn> wrote: > > > disable_pm: > > > - pm_runtime_put_noidle(&i2c->dev); > > > pm_runtime_disable(&i2c->dev); > > > ak8974_set_power(ak8974, AK8974_PWR_OFF); > > > > Keep the top pm_runtime_put_noidle(). > > I found that there was already a pm_runtime_put() before > iio_triggered_buffer_setup() (just after pm_runtime_use_autosuspend). > So if we keep the pm_runtime_put_noidle() here, we will have > two pmusage counter decrement. Do you think this is a bug? Yes you're right. What about just moving the pm_runtime_put() until the end of the initialization? Right before return 0; Then we can keep this nice goto exits as they are. Maybe move all these three: pm_runtime_set_autosuspend_delay(&i2c->dev, AK8974_AUTOSUSPEND_DELAY); pm_runtime_use_autosuspend(&i2c->dev); pm_runtime_put(&i2c->dev); Yours, Linus Walleij
> What about just moving the pm_runtime_put() until the end > of the initialization? Right before return 0; > Then we can keep this nice goto exits as they are. > > Maybe move all these three: > > pm_runtime_set_autosuspend_delay(&i2c->dev, > AK8974_AUTOSUSPEND_DELAY); > pm_runtime_use_autosuspend(&i2c->dev); > pm_runtime_put(&i2c->dev); > Good idea! Thank you for your advice and I will fix this in the next version of patch. Regards, Dinghao
diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c index d32996702110..c1bdb304eb9e 100644 --- a/drivers/iio/magnetometer/ak8974.c +++ b/drivers/iio/magnetometer/ak8974.c @@ -764,18 +764,24 @@ static int ak8974_probe(struct i2c_client *i2c, ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config); if (IS_ERR(ak8974->map)) { dev_err(&i2c->dev, "failed to allocate register map\n"); + pm_runtime_put_noidle(&i2c->dev); + pm_runtime_disable(&i2c->dev); return PTR_ERR(ak8974->map); } ret = ak8974_set_power(ak8974, AK8974_PWR_ON); if (ret) { dev_err(&i2c->dev, "could not power on\n"); + pm_runtime_put_noidle(&i2c->dev); + pm_runtime_disable(&i2c->dev); goto power_off; } ret = ak8974_detect(ak8974); if (ret) { dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n"); + pm_runtime_put_noidle(&i2c->dev); + pm_runtime_disable(&i2c->dev); goto power_off; } @@ -786,6 +792,8 @@ static int ak8974_probe(struct i2c_client *i2c, ret = ak8974_reset(ak8974); if (ret) { dev_err(&i2c->dev, "AK8974 reset failed\n"); + pm_runtime_put_noidle(&i2c->dev); + pm_runtime_disable(&i2c->dev); goto power_off; } @@ -851,7 +859,6 @@ static int ak8974_probe(struct i2c_client *i2c, cleanup_buffer: iio_triggered_buffer_cleanup(indio_dev); disable_pm: - pm_runtime_put_noidle(&i2c->dev); pm_runtime_disable(&i2c->dev); ak8974_set_power(ak8974, AK8974_PWR_OFF); power_off:
When devm_regmap_init_i2c() returns an error code, a pairing runtime PM usage counter decrement is needed to keep the counter balanced. For error paths after ak8974_set_power(), ak8974_detect() and ak8974_reset(), things are the same. However, When iio_triggered_buffer_setup() returns an error code, we don't need such a decrement because there is already one before this call. Things are the same for other error paths after it. Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> --- drivers/iio/magnetometer/ak8974.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)