From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH v3] ARM: OMAP: i2c: fix interrupt flood during resume Date: Thu, 11 Oct 2012 14:08:25 -0700 Message-ID: <87ipag90om.fsf@deeprootsystems.com> References: <1349871480-25182-1-git-send-email-kalle.jokiniemi@jollamobile.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <1349871480-25182-1-git-send-email-kalle.jokiniemi-4y2FMlU5MS8onNqTyK5kxQ@public.gmane.org> (Kalle Jokiniemi's message of "Wed, 10 Oct 2012 15:18:00 +0300") Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kalle Jokiniemi Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, grygorii.strashko-l0cyMroinI0@public.gmane.org, shubhrajyoti-l0cyMroinI0@public.gmane.org List-Id: linux-omap@vger.kernel.org Hi Kalle, Kalle Jokiniemi 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. > > Fixed the issue by adding suspend_noirq and resume_early > functions that keep i2c bus interrupts disabled until > resume_noirq has run completely. > > Issue was detected doing a wake up from autosleep with > twl4030 power key on N9. Patch tested on N9. > > Signed-off-by: Kalle Jokiniemi This version looks good, thanks for the extra comments. Reviewed-by: Kevin Hilman Tested-by: Kevin Hilman Wolfram, This should also probably be Cc'd to stable since it affects earlier kernels as well. Thanks, Kevin > --- > drivers/i2c/busses/i2c-omap.c | 34 ++++++++++++++++++++++++++++++++++ > 1 files changed, 34 insertions(+), 0 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index a0e49f6..991341b 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -1132,6 +1132,36 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev) > } > > #ifdef CONFIG_PM > +#ifdef CONFIG_PM_SLEEP > +static int omap_i2c_suspend_noirq(struct device *dev) > +{ > + > + struct platform_device *pdev = to_platform_device(dev); > + struct omap_i2c_dev *_dev = platform_get_drvdata(pdev); > + > + /* Disabling irq here to balance the enable in resume_early */ > + 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); > + > + /* > + * 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 > + * keep the bus irq disabled until all other irqs have been enabled. > + */ > + enable_irq(_dev->irq); > + > + return 0; > +} > +#endif > #ifdef CONFIG_PM_RUNTIME > static int omap_i2c_runtime_suspend(struct device *dev) > { > @@ -1183,6 +1213,10 @@ static int omap_i2c_runtime_resume(struct device *dev) > #endif /* CONFIG_PM_RUNTIME */ > > static struct dev_pm_ops omap_i2c_pm_ops = { > +#ifdef CONFIG_PM_SLEEP > + .suspend_noirq = omap_i2c_suspend_noirq, > + .resume_early = omap_i2c_resume_early, > +#endif > SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend, > omap_i2c_runtime_resume, NULL) > };