* [PATCH v4] i2c: designware-platdrv: fix unbalanced clk enable and prepare
@ 2016-04-22 8:49 Jisheng Zhang
2016-04-22 13:59 ` Jarkko Nikula
0 siblings, 1 reply; 4+ messages in thread
From: Jisheng Zhang @ 2016-04-22 8:49 UTC (permalink / raw)
To: linux-arm-kernel
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 <jszhang@marvell.com>
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v4] i2c: designware-platdrv: fix unbalanced clk enable and prepare
2016-04-22 8:49 [PATCH v4] i2c: designware-platdrv: fix unbalanced clk enable and prepare Jisheng Zhang
@ 2016-04-22 13:59 ` Jarkko Nikula
2016-04-25 9:07 ` Andy Shevchenko
0 siblings, 1 reply; 4+ messages in thread
From: Jarkko Nikula @ 2016-04-22 13:59 UTC (permalink / raw)
To: linux-arm-kernel
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 <jszhang@marvell.com>
> ---
> 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v4] i2c: designware-platdrv: fix unbalanced clk enable and prepare
2016-04-22 13:59 ` Jarkko Nikula
@ 2016-04-25 9:07 ` Andy Shevchenko
2016-04-25 9:13 ` Jisheng Zhang
0 siblings, 1 reply; 4+ messages in thread
From: Andy Shevchenko @ 2016-04-25 9:07 UTC (permalink / raw)
To: linux-arm-kernel
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 <jszhang@marvell.com>
> > ---
> > ? 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 <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v4] i2c: designware-platdrv: fix unbalanced clk enable and prepare
2016-04-25 9:07 ` Andy Shevchenko
@ 2016-04-25 9:13 ` Jisheng Zhang
0 siblings, 0 replies; 4+ messages in thread
From: Jisheng Zhang @ 2016-04-25 9:13 UTC (permalink / raw)
To: linux-arm-kernel
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 <jszhang@marvell.com>
> > > ---
> > > ? 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
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-04-25 9:13 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2016-04-22 8:49 [PATCH v4] i2c: designware-platdrv: fix unbalanced clk enable and prepare Jisheng Zhang
2016-04-22 13:59 ` Jarkko Nikula
2016-04-25 9:07 ` Andy Shevchenko
2016-04-25 9:13 ` Jisheng Zhang
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