Re: [PATCH v3] ARM: OMAP: i2c: fix interrupt flood during resume
From: Kevin Hilman <hidden>
Date: 2012-10-11 21:08:25
Also in:
linux-omap
Hi Kalle, Kalle Jokiniemi [off-list ref] 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 <redacted>
This version looks good, thanks for the extra comments. Reviewed-by: Kevin Hilman <redacted> Tested-by: Kevin Hilman <redacted> Wolfram, This should also probably be Cc'd to stable since it affects earlier kernels as well. Thanks, Kevin
quoted hunk
--- 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) };