On Mon, Aug 30, 2010 at 11:43:23AM -0700, Kevin Hilman wrote:
> Vishwanath BS <vishwanath.bs@xxxxxx> writes:
>
> > In current i2c core driver, pm_runtime_set_active call from i2c_device_pm_resume
> > is not balanced by pm_runtime_set_suspended call from i2c_device_pm_suspend.
> > pm_runtime_set_active called from resume path will increase the child_count of
> > the device's parent. However, matching pm_runtime_set_suspended is not called
> > in suspend routine because of which child_count of the device's parent
> > is not balanced, preventing the parent device to idle.
> > Issue has been fixed by adding pm_runtime_set_suspended call inside suspend
> > reoutine which will make sure that child_counts are balanced.
> > This fix has been tested on OMAP4430.
> >
> > Signed-off-by: Partha Basak <p-basak2@xxxxxx>
> > Signed-off-by: Vishwanath BS <vishwanath.bs@xxxxxx>
> >
> > Cc: Rafael J. Wysocki <rjw@xxxxxxx>
> > Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
> > Cc: Ben Dooks <ben-linux@xxxxxxxxx>
>
> Also Cc'ing Mark Brown as original author of runtime PM for i2-core.
Also Jean Delvare who maintains the I2C core. To be honest Rafael did
all the actual work here (and has since rewritten the code anyway).
> > ---
> > drivers/i2c/i2c-core.c | 12 ++++++++++--
> > 1 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index 6649176..3146bff
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -196,14 +196,22 @@ static int i2c_legacy_resume(struct device *dev)
> > static int i2c_device_pm_suspend(struct device *dev)
> > {
> > const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> > + int ret;
> >
> > if (pm_runtime_suspended(dev))
> > return 0;
> >
> > if (pm)
> > - return pm->suspend ? pm->suspend(dev) : 0;
> > + ret = pm->suspend ? pm->suspend(dev) : 0;
> > + else
> > + ret = i2c_legacy_suspend(dev, PMSG_SUSPEND);
> >
> > - return i2c_legacy_suspend(dev, PMSG_SUSPEND);
> > + if (!ret) {
> > + pm_runtime_disable(dev);
> > + pm_runtime_set_suspended(dev);
> > + pm_runtime_enable(dev);
> > + }
> > + return ret;
> > }
> >
> > static int i2c_device_pm_resume(struct device *dev)
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