PM / Runtime: Add synchronous runtime interface for interrupt handlers (v3)

This patch (as1431c) makes the synchronous runtime-PM interface
suitable for use in interrupt handlers.  Subsystems can call the new
pm_runtime_irq_safe() function to tell the PM core that a device's
runtime_suspend and runtime_resume callbacks should be invoked with
interrupts disabled and the spinlock held.  This permits the
pm_runtime_get_sync() and the new pm_runtime_put_sync_suspend()
routines to be called from within interrupt handlers.

When a device is declared irq-safe in this way, the PM core increments
the parent's usage count, so the parent will never be runtime
suspended.  This prevents difficult situations in which an irq-safe
device can't resume because it is forced to wait for its non-irq-safe
parent.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 40f3f45702ba..61f2066e6852 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -486,6 +486,7 @@ struct dev_pm_info {
         unsigned int            run_wake:1;
         unsigned int            runtime_auto:1;
         unsigned int            no_callbacks:1;
+        unsigned int            irq_safe:1;
         unsigned int            use_autosuspend:1;
         unsigned int            timer_autosuspends:1;
         enum rpm_request        request;