Manual Pages for UNIX Operating System command usage for man audio_engine_open

Driver Entry Points                         audio_engine_open(9E)



NAME
     audio_engine_open, audio_engine_close -  open  or  close  an
     audio engine

SYNOPSIS
     #include 

     int prefix_open(void *state, int flag, unsigned *nframes
          caddr_t *bufp);


     void prefix_close(void *state);


PARAMETERS
     state      pointer to driver supplied soft state


     flag       integer mask of  flags  indicating  mode  of  the
                engine.  ENGINE_INPUT  indicates  the  engine  is
                opened for recording. ENGINE_OUTPUT indicates the
                engine is opened for playback. All other possible
                bits are reserved and should be  ignored  by  the
                driver.


     nframes    pointer to an unsigned  integer  to  receive  the
                number of frames the associated buffer can hold


     bufp       pointer to receive the address of the buffer  for
                the  engine.  The  buffer  is  allocated  by  the
                engine, and is a circular FIFO big enough to hold
                all  of the frames configured. The driver has the
                responsibility for managing any resources associ-
                ated  with the buffer. The driver should not make
                any assumptions about the type of accesses to the
                buffer  made  by  the  framework  or application.
                Therefore,   it   should   be   configured   with
                DDI_NEVERSWAP_ACC  if  the  buffer  is  allocated
                using ddi_dma_mem_alloc(9F).


INTERFACE LEVEL
     Solaris DDI specific (Solaris DDI)

DESCRIPTION
     The audio_engine_open() function opens and  initializes  the
     DMA  engine  and configures any associated hardware (such as
     sample rate or format conversion logic) for the device.





SunOS 5.11          Last change: 16 Apr 2010                    1






Driver Entry Points                         audio_engine_open(9E)



     The audio_engine_open() function also ensures that resources
     for the data buffer are properly allocated and that the cir-
     cular buffer is primed and ready for use  by  the  framework
     and audio clients.


     The audio_engine_open() function does not actually start any
     data  transfer,  but  merely does much of the initialization
     work. It can perform expensive operations, including  sleep-
     ing allocations or blocking on resources.


     The audio_engine_close()  function  undoes  the  effects  of
     audio_engine_open()and  may  deallocate  resources that were
     allocated during audio_engine_open(). The framework  ensures
     that  audio_engine_stop(9E)  is issued on any running engine
     before calling audio_engine_close().


     Once audio_engine_close() returns, the frame counter for the
     engine must be reset to 0.


     The framework will not  access  the  device  buffer  for  an
     engine that is not open, so buffer resources may be released
     at this point.

RETURN VALUES
     The audio_engine_open() function returns 0 on success or  an
     error  number  on  failure.  See  open(2) for possible error
     numbers.

CONTEXT
     The audio_engine_open() and  audio_engine_close()  functions
     are called from user or kernel context only.

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



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


SEE ALSO
     open(2),        attributes(5),        audio_engine_stop(9E),
     ddi_dma_mem_alloc(9F), audio_engine_ops(9S)



SunOS 5.11          Last change: 16 Apr 2010                    2