rem: RemIntServer( INTB_PORTS, audioctrl->ahiac_PPCMixInterrupt );
add: if( audioctrl->ahiac_PPCMixInterrupt != NULL ) { RemIntServer( INTB_PORTS, audioctrl->ahiac_PPCMixInterrupt ); }
context: CleanUpMixroutine( struct AHIPrivAudioCtrl *audioctrl ){//kprintf( "CleanUpMixroutine\n" );  RemIntServer( INTB_PORTS, audioctrl->ahiac_PPCMixInterrupt );  FreeVec( audioctrl->ahiac_PPCMixInterrupt );  AHIFreeVec( audioctrl->ahiac_PPCMixBuffer );  AHIFreeVec( audioctrl->ahiac_SoundDatas );  AHIFreeVec( audioctrl->ahiac_ChannelDatas );}