If i2c_dw_probe() fails, we should disable and unprepare the clock,
otherwise the clock enable and prepare is left unbalanced.
In dw_i2c_plat_remove(), we'd better to not rely on runtime PM to
disable and unprepare the clock since CONFIG_PM may be disabled when
configuring the kernel. So we explicitly disable and unprepare the
clock in dw_i2c_plat_remove() rather than implicitly rely on
pm_runtime_put_sync(). To keep the device usage count balanced, we
call pm_runtime_put_noidle() to decrease the usage count.
Signed-off-by: Jisheng Zhang <[email protected]>
---
Since v3:
- use runtime PM rather than rpm in commit msg
- remove duplicated "(" in commit msg
Since v2:
- s/clk/clock
- describe why use pm_runtime_put_noidle()
Since v1:
- fix commit msg: "not rely on rpm" rather than "rely on rpm"
- call i2c_dw_plat_prepare_clk after pm_rumtime_disable()
drivers/i2c/busses/i2c-designware-platdrv.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index d656657..a771781 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -253,8 +253,11 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
}
r = i2c_dw_probe(dev);
- if (r && !dev->pm_runtime_disabled)
- pm_runtime_disable(&pdev->dev);
+ if (r) {
+ if (!dev->pm_runtime_disabled)
+ pm_runtime_disable(&pdev->dev);
+ i2c_dw_plat_prepare_clk(dev, false);
+ }
return r;
}
@@ -264,15 +267,16 @@ static int dw_i2c_plat_remove(struct platform_device *pdev)
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
pm_runtime_get_sync(&pdev->dev);
+ pm_runtime_dont_use_autosuspend(&pdev->dev);
+ if (!dev->pm_runtime_disabled)
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_put_noidle(&pdev->dev);
i2c_del_adapter(&dev->adapter);
i2c_dw_disable(dev);
- pm_runtime_dont_use_autosuspend(&pdev->dev);
- pm_runtime_put_sync(&pdev->dev);
- if (!dev->pm_runtime_disabled)
- pm_runtime_disable(&pdev->dev);
+ i2c_dw_plat_prepare_clk(dev, false);
return 0;
}
--
2.8.1
Hi
On 04/22/2016 11:49 AM, Jisheng Zhang wrote:
> If i2c_dw_probe() fails, we should disable and unprepare the clock,
> otherwise the clock enable and prepare is left unbalanced.
>
> In dw_i2c_plat_remove(), we'd better to not rely on runtime PM to
> disable and unprepare the clock since CONFIG_PM may be disabled when
> configuring the kernel. So we explicitly disable and unprepare the
> clock in dw_i2c_plat_remove() rather than implicitly rely on
> pm_runtime_put_sync(). To keep the device usage count balanced, we
> call pm_runtime_put_noidle() to decrease the usage count.
>
> Signed-off-by: Jisheng Zhang <[email protected]>
> ---
> Since v3:
> - use runtime PM rather than rpm in commit msg
> - remove duplicated "(" in commit msg
>
> Since v2:
> - s/clk/clock
> - describe why use pm_runtime_put_noidle()
>
> Since v1:
> - fix commit msg: "not rely on rpm" rather than "rely on rpm"
> - call i2c_dw_plat_prepare_clk after pm_rumtime_disable()
> drivers/i2c/busses/i2c-designware-platdrv.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index d656657..a771781 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -253,8 +253,11 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
> }
>
> r = i2c_dw_probe(dev);
> - if (r && !dev->pm_runtime_disabled)
> - pm_runtime_disable(&pdev->dev);
> + if (r) {
> + if (!dev->pm_runtime_disabled)
> + pm_runtime_disable(&pdev->dev);
> + i2c_dw_plat_prepare_clk(dev, false);
> + }
>
> return r;
> }
> @@ -264,15 +267,16 @@ static int dw_i2c_plat_remove(struct platform_device *pdev)
> struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
>
> pm_runtime_get_sync(&pdev->dev);
> + pm_runtime_dont_use_autosuspend(&pdev->dev);
> + if (!dev->pm_runtime_disabled)
> + pm_runtime_disable(&pdev->dev);
> + pm_runtime_put_noidle(&pdev->dev);
>
> i2c_del_adapter(&dev->adapter);
>
> i2c_dw_disable(dev);
>
> - pm_runtime_dont_use_autosuspend(&pdev->dev);
> - pm_runtime_put_sync(&pdev->dev);
> - if (!dev->pm_runtime_disabled)
> - pm_runtime_disable(&pdev->dev);
> + i2c_dw_plat_prepare_clk(dev, false);
>
This feels a bit an invasive change to me for unbalanced clock
enable/disable and I noticed this changes semantics how
drivers/acpi/acpi_lpss.c devices are shutdown when removing the driver.
Although I didn't notice does it cause any regression.
Before patch:
1. drivers/base/dd.c: __device_release_driver()
- pm_runtime_get_sync()
-> acpi_device_set_power(D0)
acpi_lpss_restore_ctx()
dw_i2c_plat_resume()
2. dw_i2c_plat_remove()
- pm_runtime_dont_use_autosuspend()
pm_runtime_put_sync()
-> dw_i2c_plat_suspend()
acpi_lpss_save_ctx()
acpi_device_set_power(D3)
3. __device_release_driver() continue
- dev->pm_domain->dismiss(dev)
-> acpi_lpss_dismiss() ... -> acpi_device_set_power(D3)
After patch:
1. drivers/base/dd.c: __device_release_driver()
- pm_runtime_get_sync()
-> acpi_device_set_power(D0)
acpi_lpss_restore_ctx()
dw_i2c_plat_resume()
2. dw_i2c_plat_remove()
- pm_runtime_dont_use_autosuspend()
pm_runtime_put_noidle()
* no device suspending and acpi_lpss_save_ctx()
3. __device_release_driver() continue
- dev->pm_domain->dismiss(dev)
-> acpi_lpss_dismiss() ... -> acpi_device_set_power(D3)
* powers down here
So after patch there is no acpi_lpss_save_ctx() call but I don't see
does it cause any issue here. Maybe it's better to track clock only.
What you think Andy?
--
Jarkko
On Fri, 2016-04-22 at 16:59 +0300, Jarkko Nikula wrote:
> Hi
>
> On 04/22/2016 11:49 AM, Jisheng Zhang wrote:
> >
> > If i2c_dw_probe() fails, we should disable and unprepare the clock,
> > otherwise the clock enable and prepare is left unbalanced.
> >
> > In dw_i2c_plat_remove(), we'd better to not rely on runtime PM to
> > disable and unprepare the clock since CONFIG_PM may be disabled when
> > configuring the kernel. So we explicitly disable and unprepare the
> > clock in dw_i2c_plat_remove() rather than implicitly rely on
> > pm_runtime_put_sync(). To keep the device usage count balanced, we
> > call pm_runtime_put_noidle() to decrease the usage count.
> >
> > Signed-off-by: Jisheng Zhang <[email protected]>
> > ---
> > Since v3:
> > - use runtime PM rather than rpm in commit msg
> > - remove duplicated "(" in commit msg
> >
> > Since v2:
> > - s/clk/clock
> > - describe why use pm_runtime_put_noidle()
> >
> > Since v1:
> > - fix commit msg: "not rely on rpm" rather than "rely on rpm"
> > - call i2c_dw_plat_prepare_clk after pm_rumtime_disable()
> > drivers/i2c/busses/i2c-designware-platdrv.c | 16 ++++++++++------
> > 1 file changed, 10 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
> > b/drivers/i2c/busses/i2c-designware-platdrv.c
> > index d656657..a771781 100644
> > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > @@ -253,8 +253,11 @@ static int dw_i2c_plat_probe(struct
> > platform_device *pdev)
> > }
> >
> > r = i2c_dw_probe(dev);
> > - if (r && !dev->pm_runtime_disabled)
> > - pm_runtime_disable(&pdev->dev);
> > + if (r) {
> > + if (!dev->pm_runtime_disabled)
> > + pm_runtime_disable(&pdev->dev);
> > + i2c_dw_plat_prepare_clk(dev, false);
> > + }
> >
> > return r;
> > }
> > @@ -264,15 +267,16 @@ static int dw_i2c_plat_remove(struct
> > platform_device *pdev)
> > struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
> >
> > pm_runtime_get_sync(&pdev->dev);
> > + pm_runtime_dont_use_autosuspend(&pdev->dev);
> > + if (!dev->pm_runtime_disabled)
> > + pm_runtime_disable(&pdev->dev);
> > + pm_runtime_put_noidle(&pdev->dev);
> >
> > i2c_del_adapter(&dev->adapter);
> >
> > i2c_dw_disable(dev);
> >
> > - pm_runtime_dont_use_autosuspend(&pdev->dev);
> > - pm_runtime_put_sync(&pdev->dev);
> > - if (!dev->pm_runtime_disabled)
> > - pm_runtime_disable(&pdev->dev);
> > + i2c_dw_plat_prepare_clk(dev, false);
> >
> This feels a bit an invasive change to me for unbalanced clock
> enable/disable and I noticed this changes semantics how
> drivers/acpi/acpi_lpss.c devices are shutdown when removing the
> driver.
> Although I didn't notice does it cause any regression.
>
> Before patch:
> 1. drivers/base/dd.c: __device_release_driver()
> - pm_runtime_get_sync()
> -> acpi_device_set_power(D0)
> acpi_lpss_restore_ctx()
> dw_i2c_plat_resume()
> 2. dw_i2c_plat_remove()
> - pm_runtime_dont_use_autosuspend()
> pm_runtime_put_sync()
> -> dw_i2c_plat_suspend()
> acpi_lpss_save_ctx()
> acpi_device_set_power(D3)
> 3. __device_release_driver() continue
> - dev->pm_domain->dismiss(dev)
> -> acpi_lpss_dismiss() ... -> acpi_device_set_power(D3)
>
> After patch:
> 1. drivers/base/dd.c: __device_release_driver()
> - pm_runtime_get_sync()
> -> acpi_device_set_power(D0)
> acpi_lpss_restore_ctx()
> dw_i2c_plat_resume()
> 2. dw_i2c_plat_remove()
> - pm_runtime_dont_use_autosuspend()
> pm_runtime_put_noidle()
> * no device suspending and acpi_lpss_save_ctx()
> 3. __device_release_driver() continue
> - dev->pm_domain->dismiss(dev)
> -> acpi_lpss_dismiss() ... -> acpi_device_set_power(D3)
> * powers down here
>
> So after patch there is no acpi_lpss_save_ctx() call but I don't see
> does it cause any issue here. Maybe it's better to track clock only.
> What you think Andy?
Now it looks like two fixes in one patch. From the commit message I
didn't get the relation between change runtime PM call (one to the
other) and clock (un)preparation.
--
Andy Shevchenko <[email protected]>
Intel Finland Oy
Dear Andy
On Mon, 25 Apr 2016 12:07:15 +0300 Andy Shevchenko wrote:
> On Fri, 2016-04-22 at 16:59 +0300, Jarkko Nikula wrote:
> > Hi
> >
> > On 04/22/2016 11:49 AM, Jisheng Zhang wrote:
> > >
> > > If i2c_dw_probe() fails, we should disable and unprepare the clock,
> > > otherwise the clock enable and prepare is left unbalanced.
> > >
> > > In dw_i2c_plat_remove(), we'd better to not rely on runtime PM to
> > > disable and unprepare the clock since CONFIG_PM may be disabled when
> > > configuring the kernel. So we explicitly disable and unprepare the
> > > clock in dw_i2c_plat_remove() rather than implicitly rely on
> > > pm_runtime_put_sync(). To keep the device usage count balanced, we
> > > call pm_runtime_put_noidle() to decrease the usage count.
> > >
> > > Signed-off-by: Jisheng Zhang <[email protected]>
> > > ---
> > > Since v3:
> > > - use runtime PM rather than rpm in commit msg
> > > - remove duplicated "(" in commit msg
> > >
> > > Since v2:
> > > - s/clk/clock
> > > - describe why use pm_runtime_put_noidle()
> > >
> > > Since v1:
> > > - fix commit msg: "not rely on rpm" rather than "rely on rpm"
> > > - call i2c_dw_plat_prepare_clk after pm_rumtime_disable()
> > > drivers/i2c/busses/i2c-designware-platdrv.c | 16 ++++++++++------
> > > 1 file changed, 10 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
> > > b/drivers/i2c/busses/i2c-designware-platdrv.c
> > > index d656657..a771781 100644
> > > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > > @@ -253,8 +253,11 @@ static int dw_i2c_plat_probe(struct
> > > platform_device *pdev)
> > > }
> > >
> > > r = i2c_dw_probe(dev);
> > > - if (r && !dev->pm_runtime_disabled)
> > > - pm_runtime_disable(&pdev->dev);
> > > + if (r) {
> > > + if (!dev->pm_runtime_disabled)
> > > + pm_runtime_disable(&pdev->dev);
> > > + i2c_dw_plat_prepare_clk(dev, false);
> > > + }
> > >
> > > return r;
> > > }
> > > @@ -264,15 +267,16 @@ static int dw_i2c_plat_remove(struct
> > > platform_device *pdev)
> > > struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
> > >
> > > pm_runtime_get_sync(&pdev->dev);
> > > + pm_runtime_dont_use_autosuspend(&pdev->dev);
> > > + if (!dev->pm_runtime_disabled)
> > > + pm_runtime_disable(&pdev->dev);
> > > + pm_runtime_put_noidle(&pdev->dev);
> > >
> > > i2c_del_adapter(&dev->adapter);
> > >
> > > i2c_dw_disable(dev);
> > >
> > > - pm_runtime_dont_use_autosuspend(&pdev->dev);
> > > - pm_runtime_put_sync(&pdev->dev);
> > > - if (!dev->pm_runtime_disabled)
> > > - pm_runtime_disable(&pdev->dev);
> > > + i2c_dw_plat_prepare_clk(dev, false);
> > >
> > This feels a bit an invasive change to me for unbalanced clock
> > enable/disable and I noticed this changes semantics how
> > drivers/acpi/acpi_lpss.c devices are shutdown when removing the
> > driver.
> > Although I didn't notice does it cause any regression.
> >
> > Before patch:
> > 1. drivers/base/dd.c: __device_release_driver()
> > - pm_runtime_get_sync()
> > -> acpi_device_set_power(D0)
> > acpi_lpss_restore_ctx()
> > dw_i2c_plat_resume()
> > 2. dw_i2c_plat_remove()
> > - pm_runtime_dont_use_autosuspend()
> > pm_runtime_put_sync()
> > -> dw_i2c_plat_suspend()
> > acpi_lpss_save_ctx()
> > acpi_device_set_power(D3)
> > 3. __device_release_driver() continue
> > - dev->pm_domain->dismiss(dev)
> > -> acpi_lpss_dismiss() ... -> acpi_device_set_power(D3)
> >
> > After patch:
> > 1. drivers/base/dd.c: __device_release_driver()
> > - pm_runtime_get_sync()
> > -> acpi_device_set_power(D0)
> > acpi_lpss_restore_ctx()
> > dw_i2c_plat_resume()
> > 2. dw_i2c_plat_remove()
> > - pm_runtime_dont_use_autosuspend()
> > pm_runtime_put_noidle()
> > * no device suspending and acpi_lpss_save_ctx()
> > 3. __device_release_driver() continue
> > - dev->pm_domain->dismiss(dev)
> > -> acpi_lpss_dismiss() ... -> acpi_device_set_power(D3)
> > * powers down here
> >
> > So after patch there is no acpi_lpss_save_ctx() call but I don't see
> > does it cause any issue here. Maybe it's better to track clock only.
> > What you think Andy?
>
> Now it looks like two fixes in one patch. From the commit message I
> didn't get the relation between change runtime PM call (one to the
> other) and clock (un)preparation.
>
I'm not sure I got your points. There are two unbalanced clk enable and
prepare issues before the patch:
one is in the i2c_dw_probe() failure path. another is in the remove path when
CONFIG_PM is disabled.
The patch addresses this unbalance.
Thanks,
Jisheng