* [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error
@ 2020-05-24 2:51 Dinghao Liu
2020-05-25 12:08 ` Linus Walleij
0 siblings, 1 reply; 5+ messages in thread
From: Dinghao Liu @ 2020-05-24 2:51 UTC (permalink / raw)
To: dinghao.liu, kjlu
Cc: Linus Walleij, Jonathan Cameron, Hartmut Knaack,
Lars-Peter Clausen, Peter Meerwald-Stadler, linux-iio,
linux-kernel
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(-)
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:
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error
2020-05-24 2:51 [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error Dinghao Liu
@ 2020-05-25 12:08 ` Linus Walleij
2020-05-26 5:14 ` dinghao.liu
0 siblings, 1 reply; 5+ messages in thread
From: Linus Walleij @ 2020-05-25 12:08 UTC (permalink / raw)
To: Dinghao Liu
Cc: Kangjie Lu, Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, linux-iio, linux-kernel
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
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: Re: [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error
2020-05-25 12:08 ` Linus Walleij
@ 2020-05-26 5:14 ` dinghao.liu
2020-05-26 9:31 ` Linus Walleij
0 siblings, 1 reply; 5+ messages in thread
From: dinghao.liu @ 2020-05-26 5:14 UTC (permalink / raw)
To: Linus Walleij
Cc: Kangjie Lu, Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, linux-iio, linux-kernel
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
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: Re: [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error
2020-05-26 5:14 ` dinghao.liu
@ 2020-05-26 9:31 ` Linus Walleij
2020-05-26 10:05 ` dinghao.liu
0 siblings, 1 reply; 5+ messages in thread
From: Linus Walleij @ 2020-05-26 9:31 UTC (permalink / raw)
To: Dinghao Liu
Cc: Kangjie Lu, Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, linux-iio, linux-kernel
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
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: Re: Re: [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error
2020-05-26 9:31 ` Linus Walleij
@ 2020-05-26 10:05 ` dinghao.liu
0 siblings, 0 replies; 5+ messages in thread
From: dinghao.liu @ 2020-05-26 10:05 UTC (permalink / raw)
To: Linus Walleij
Cc: Kangjie Lu, Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, linux-iio, linux-kernel
> 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
^ permalink raw reply [flat|nested] 5+ messages in thread
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2020-05-24 2:51 [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error Dinghao Liu
2020-05-25 12:08 ` Linus Walleij
2020-05-26 5:14 ` dinghao.liu
2020-05-26 9:31 ` Linus Walleij
2020-05-26 10:05 ` dinghao.liu
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