Name
enable_irq — 
     enable handling of an irq
 
Synopsis
| void enable_irq ( | unsigned int irq ); | 
 
Description
   Undoes the effect of one call to disable_irq.  If this
   matches the last disable, processing of interrupts on this
   IRQ line is re-enabled.
   
   This function may be called from IRQ context only when
   desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !