mfd: arizona: Fix race between runtime suspend and IRQs
The function arizona_irq_thread (the threaded handler for the arizona IRQs) calls pm_runtime_get_sync at the start to ensure that the chip is active as we handle the IRQ. If the chip is part way through a runtime suspend when an IRQ arrives the PM core will wait for the suspend to complete, before resuming. However, since commit 4f0216409f7c ("mfd: arizona: Add better support for system suspend") the runtime suspend function may call disable_irq, if the chip is going to fully power off, which will try to wait for any outstanding IRQs to complete. This results in deadlock as the IRQ thread is waiting for the PM operation to complete and the PM thread is waiting for the IRQ to complete. To avoid this situation we use disable_irq_nosync, which allows the suspending thread to finish the suspend without waiting for the IRQ to complete. This is safe because if an IRQ is being processed it can only be blocked at the pm_runtime_get_sync at the start of the handler otherwise it wouldn't be possible to suspend. Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
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@ -651,7 +651,7 @@ static int arizona_runtime_suspend(struct device *dev)
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arizona->has_fully_powered_off = true;
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disable_irq(arizona->irq);
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disable_irq_nosync(arizona->irq);
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arizona_enable_reset(arizona);
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regulator_bulk_disable(arizona->num_core_supplies,
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arizona->core_supplies);
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