Re: [PATCH] PM / runtime: Allow an irq-safe parent to be runtime suspended
From: Ulf Hansson <hidden>
Date: 2017-12-01 07:35:51
On 17 November 2017 at 14:16, Ulf Hansson [off-list ref] wrote:
When pm_runtime_irq_safe() is a called for a child device, it's assumed that the parent is never also irq-safe. Therefore, is the parent runtime resumed and the usage counter increased for it, as to avoid having an irq-safe child waiting for non-irq-safe parent. Improve this behaviour by taking into account that the parent could also be irq-safe. In such case let's allow it to be runtime suspended. Signed-off-by: Ulf Hansson <redacted>
Rafael, I noticed you applied this for next, but I realized that I have overlooked a couple of more things that needs to be taken care of. Can you please drop this version? I will re-spin a new version soon. Kind regards Uffe
quoted hunk ↗ jump to hunk
--- drivers/base/power/runtime.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index ec059750..d44f520 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c@@ -1370,13 +1370,13 @@ EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks); * Set the power.irq_safe flag, which tells the PM core that the * ->runtime_suspend() and ->runtime_resume() callbacks for this device should * always be invoked with the spinlock held and interrupts disabled. It also - * causes the parent's usage counter to be permanently incremented, preventing - * the parent from runtime suspending -- otherwise an irq-safe child might have - * to wait for a non-irq-safe parent. + * causes the parent's usage counter to be permanently incremented, unless the + * parent is also irq-safe. This prevents the parent from runtime suspending, + * otherwise an irq-safe child might have to wait for a non-irq-safe parent. */ void pm_runtime_irq_safe(struct device *dev) { - if (dev->parent) + if (dev->parent && !pm_runtime_is_irq_safe(dev->parent)) pm_runtime_get_sync(dev->parent); spin_lock_irq(&dev->power.lock); dev->power.irq_safe = 1;@@ -1507,7 +1507,7 @@ void pm_runtime_reinit(struct device *dev) spin_lock_irq(&dev->power.lock); dev->power.irq_safe = 0; spin_unlock_irq(&dev->power.lock); - if (dev->parent) + if (dev->parent && !pm_runtime_is_irq_safe(dev->parent)) pm_runtime_put(dev->parent); } } --2.7.4