Kernel Functions for Drivers                 ddiintrhilevel(9F)



NAME
     ddiintrhilevel - indicate interrupt handler type

SYNOPSIS
     #include 
     #include 



     int ddiintrhilevel(devinfot *dip, uintt inumber);


INTERFACE LEVEL
     Solaris  DI  specific  (Solaris  DI).  This  interface  is
     obsolete.  Use  the  new  interrupt interfaces referenced in
     Intro(9F). Refer to Writing Device Drivers for more informa-
     tion.

PARAMETERS
     dip        Pointer to devinfo structure.


     inumber    Interrupt number.


DESCRIPTION
     The ddiintrhilevel()  function  returns  non-zero  if  the
     specified interrupt is a "high level" interrupt.


     High level interrupts must be handled without  using  system
     services  that  manipulate thread or process states, because
     these interrupts are not blocked by the scheduler.


     In addition, high level interrupt handlers must take care to
     do a minimum of work because they are not preemptable.


     A typical high level interrupt handler would put data into a
     circular  buffer  and  schedule  a soft interrupt by calling
     dditriggersoftintr(). The circular buffer  could  be  pro-
     tected  by  using  a mutex that was properly initialized for
     the interrupt handler.


     The ddiintrhilevel() function can be used  before  calling
     ddiaddintr()  to  decide  which  type of interrupt handler
     should be used. Most device drivers are  designed  with  the
     knowledge that the devices they support will always generate
     low level interrupts,  however  some  devices,  for  example
     those using SBus or VME bus level 6 or 7 interrupts must use



SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                 ddiintrhilevel(9F)



     this test because on some machines those interrupts are high
     level (above the scheduler level) and on other machines they
     are not.

RETURN VALUES
     non-zero    indicates a high-level interrupt.


CONTEXT
     These functions can be called from useruser,  interrupt,  or
     kernel context.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Obsolete                    
    


SEE ALSO
     ddiaddintr(9F), Intro(9F), mutex(9F)


     Writing Device Drivers

























SunOS 5.11          Last change: 16 Jan 2006                    2