pe, 2012-10-05 kello 15:07 -0700, Kevin Hilman kirjoitti:
> +Grygorii (who's been working on various I2C related suspend/resume
> issues also)
>
> Hi Kalle,
>
> Kalle Jokiniemi <kalle.jokiniemi@xxxxxxxxxxxxxxx> writes:
>
> > The resume_noirq enables interrupts one-by-one starting from
> > first one. Now if the wake up event for suspend came from i2c
> > device, the i2c bus irq gets enabled before the threaded
> > i2c device irq, causing a flood of i2c bus interrupts as the
> > threaded irq that should clear the event is not enabled yet.
>
> Ugh, another reason we need some sort of driver dependency tracking in the
> driver model.
>
> > Fixed the issue by adding suspend_late and resume_early
> > functions that keep i2c bus interrupts disabled until
> > resume_noirq has run completely.
>
> Hmm, any reason we couldn't put the disable in the .suspend_noirq
> callback?
I just liked the symmetry of late/early.
> The reason being is that other drivers might use I2C in their
> suspend or late_suspend callbacks. I'm not aware of any using I2C in
> their late_suspend callbacks in mainline, but in theory I2C should work
> all the way through the late callbacks.
Makes sense, I'll change that.
>
> I know it might look strange to have a disable_irq() in the noirq
> callback, since IRQs are already disabled at that point, but a comment
> stating that it's just there to balance the (re)enable in the
> early_resume callback should be clear.
>
> Some other minor comments below...
>
> > Issue was detected doing a wake up from autosleep with
> > twl4030 power key on N9. Patch tested on N9.
> >
> > Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@xxxxxxxxxxxxxxx>
> > ---
> > drivers/i2c/busses/i2c-omap.c | 37 +++++++++++++++++++++++++++++++++++++
> > 1 files changed, 37 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> > index 801df60..b77b0c2 100644
> > --- a/drivers/i2c/busses/i2c-omap.c
> > +++ b/drivers/i2c/busses/i2c-omap.c
> > @@ -1158,6 +1158,35 @@ omap_i2c_remove(struct platform_device *pdev)
> > return 0;
> > }
> >
> > +#ifdef CONFIG_SUSPEND
>
> This should be CONFIG_PM_SLEEP in order to cover hibernation also.
Ok, I'll fix these, thanks.
>
> > +static int omap_i2c_suspend_late(struct device *dev)
> > +{
> > +
> > + struct platform_device *pdev = to_platform_device(dev);
> > + struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
> > +
> > + /*
> > + * The noirq_resume enables the interrupts one by one,
> > + * this causes a interrupt flood if the SW irq actually reading
> > + * event from i2c device is enabled only after i2c bus irq, as the
> > + * irq that should clear the event is still disabled. We have to
> > + * disable the bus irq until all other irqs have been enabled.
> > + */
>
> This comment probably belongs in the resume handler.
Ok. I'll move it.
- Kalle
>
> > + disable_irq(_dev->irq);
> > + return 0;
> > +}
> > +
> > +static int omap_i2c_resume_early(struct device *dev)
> > +{
> > +
> > + struct platform_device *pdev = to_platform_device(dev);
> > + struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);
> > +
> > + enable_irq(_dev->irq);
> > +
> > + return 0;
> > +}
> > +#endif
> > #ifdef CONFIG_PM_RUNTIME
> > static int omap_i2c_runtime_suspend(struct device *dev)
> > {
> > @@ -1178,10 +1207,18 @@ static int omap_i2c_runtime_resume(struct device *dev)
> >
> > return 0;
> > }
> > +#endif
> >
> > +#if defined(CONFIG_SUSPEND) || defined(CONFIG_PM_RUNTIME)
>
> #ifdef CONFIG_PM will cover this
>
> > static struct dev_pm_ops omap_i2c_pm_ops = {
> > +#ifdef CONFIG_SUSPEND
>
> again, CONFIG_PM_SLEEP here
>
> > + .suspend_late = omap_i2c_suspend_late,
> > + .resume_early = omap_i2c_resume_early,
> > +#endif
> > +#ifdef CONFIG_PM_RUNTIME
> > .runtime_suspend = omap_i2c_runtime_suspend,
> > .runtime_resume = omap_i2c_runtime_resume,
> > +#endif
> > };
> > #define OMAP_I2C_PM_OPS (&omap_i2c_pm_ops)
> > #else
>
> Kevin
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