Manual Pages for UNIX Operating System command usage for man ddi_intr_get_hilevel_pri

Kernel Functions for Drivers         ddi_intr_get_hilevel_pri(9F)



NAME
     ddi_intr_get_hilevel_pri - get minimum priority level for  a
     high-level interrupt

SYNOPSIS
     #include 
     #include 
     #include 
     #include 

     int ddi_intr_get_hilevel_pri(void);


INTERFACE LEVEL
     Solaris DDI specific (Solaris DDI).

DESCRIPTION
     Upon a  successful  return,  the  ddi_intr_get_hilevel_pri()
     function returns the minimum priority level for a high-level
     interrupt. The return priority value can be used to  compare
     to  other  priority  values,  such  as  those  returned from
     ddi_intr_get_pri(9F), to  determine  if  a  given  interrupt
     priority is a high-level interrupt.


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


     In addition, high-level interrupt handlers must take care to
     do a minimum of work because they cannot be preempted.


     A typical high-level interrupt handler puts data into a cir-
     cular  buffer  and  schedule  a  soft  interrupt  by calling
     ddi_intr_trigger_softint(). The circular buffer can be  pro-
     tected by using a mutex that is properly initialized for the
     interrupt handler.


     The ddi_intr_get_hilevel_pri() function can be  used  before
     calling  ddi_intr_add_handler() to help determine which type
     of interrupt handler can be used. Most  device  drivers  are
     designed  with  the  knowledge that supported devices always
     generate low level interrupts. On  some  machines,  however,
     interrupts  are  high-level above the scheduler level and on
     other machines they are not. Devices  such  as  those  those
     using  SBus  interrupts  or  VME bus level 6 or 7 interrupts
     must use the ddi_intr_get_hilevel_pri() function to test the
     type of interrupt handler that can be used.




SunOS 5.11          Last change: 07 Apr 2005                    1






Kernel Functions for Drivers         ddi_intr_get_hilevel_pri(9F)



RETURN VALUES
     The ddi_intr_get_hilevel_pri() function returns the priority
     value for a high-level interrupt.

CONTEXT
     The ddi_intr_get_hilevel_pri() function can be  called  from
     either user or kernel non-interrupt context.

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



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|


SEE ALSO
     attributes(5), ddi_intr_add_handler(9F), ddi_intr_alloc(9F),
     ddi_intr_enable(9F),                   ddi_intr_get_pri(9F),
     ddi_intr_trigger_softint(9F), mutex(9F)


     Writing Device Drivers



























SunOS 5.11          Last change: 07 Apr 2005                    2