2 files changed, 29 insertions, 2 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index b48eae32dc61..6e59ac05ef2a 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -58,6 +58,7 @@
 #define IRQ_NOREQUEST           0x04000000      /* IRQ cannot be requested */
 #define IRQ_NOAUTOEN            0x08000000      /* IRQ will not be enabled on request irq */
 #define IRQ_DELAYED_DISABLE     0x10000000      /* IRQ disable (masking) happens delayed. */
+#define IRQ_WAKEUP              0x20000000      /* IRQ triggers system wakeup */
 
 struct proc_dir_entry;
 
@@ -124,6 +125,7 @@ struct irq_chip {
  * @action:             the irq action chain
  * @status:             status information
  * @depth:              disable-depth, for nested irq_disable() calls
+ * @wake_depth:         enable depth, for multiple set_irq_wake() callers
  * @irq_count:          stats field to detect stalled irqs
  * @irqs_unhandled:     stats field for spurious unhandled interrupts
  * @lock:               locking for SMP
@@ -147,6 +149,7 @@ struct irq_desc {
         unsigned int            status;         /* IRQ status */
 
         unsigned int            depth;          /* nested irq disables */
+        unsigned int            wake_depth;     /* nested wake enables */
         unsigned int            irq_count;      /* For detecting broken IRQs */
         unsigned int            irqs_unhandled;
         spinlock_t              lock;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 4e461438e48b..92be519eff26 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -137,16 +137,40 @@ EXPORT_SYMBOL(enable_irq);
  *      @irq:   interrupt to control
  *      @on:    enable/disable power management wakeup
  *
- *      Enable/disable power management wakeup mode
+ *      Enable/disable power management wakeup mode, which is
+ *      disabled by default.  Enables and disables must match,
+ *      just as they match for non-wakeup mode support.
+ *
+ *      Wakeup mode lets this IRQ wake the system from sleep
+ *      states like "suspend to RAM".
  */
 int set_irq_wake(unsigned int irq, unsigned int on)
 {
         struct irq_desc *desc = irq_desc + irq;
         unsigned long flags;
         int ret = -ENXIO;
+        int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
 
+        /* wakeup-capable irqs can be shared between drivers that
+         * don't need to have the same sleep mode behaviors.
+         */
         spin_lock_irqsave(&desc->lock, flags);
-        if (desc->chip->set_wake)
+        if (on) {
+                if (desc->wake_depth++ == 0)
+                        desc->status |= IRQ_WAKEUP;
+                else
+                        set_wake = NULL;
+        } else {
+                if (desc->wake_depth == 0) {
+                        printk(KERN_WARNING "Unbalanced IRQ %d "
+                                        "wake disable\n", irq);
+                        WARN_ON(1);
+                } else if (--desc->wake_depth == 0)
+                        desc->status &= ~IRQ_WAKEUP;
+                else
+                        set_wake = NULL;
+        }
+        if (set_wake)
                 ret = desc->chip->set_wake(irq, on);
         spin_unlock_irqrestore(&desc->lock, flags);
         return ret;