Index for Section 9

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drvr_register_flush(9r)
NAME
  drvr_register_flush - General: Registers or deregisters a flush interface

SYNOPSIS
  void drvr_register_flush(
	  void (*callback)(),
	  caddr_t parameter,
	  int flags );

ARGUMENTS
  callback
      Specifies the name of the device driver interface to be registered or
      deregistered by drvr_register_flush. When registered, this is the flush
      interface that the kernel calls just prior to system shutdown.

  parameter
      Specifies a parameter that the device driver needs the kernel to pass
      to the registered driver flush interface. For example, you could pass a
      pointer to a device structure and the kernel passes this to the
      driver's registered flush interface.

  flags
      Specifies whether to register or deregister the device driver's flush
      interface. You can pass one of the following constants:

      DRVR_REGISTER
	      Registers a device driver's flush interface.

      DRVR_UNREGISTER
	      Deregisters a device driver's flush interface.

DESCRIPTION
  The drvr_register_flush interface registers or deregisters a flush
  interface to be called when the system performs a system shutdown.  The
  kernel calls this interface just prior to system shutdown. The
  drvr_register_flush interface allows device drivers to ensure that all I/O
  to a bus adapter has been completed. Some bus adapters are asynchronous to
  the system bus (containing buffers) and need to be cleared out (that is,
  flushed).

NOTES
  Device drivers should call the drvr_register_flush interface if it is
  necessary to call a flush interface before the kernel performs a dump
  operation. Device drivers should call the drvr_register_shutdown interface
  if it is necessary to call a shutdown interface that the kernel calls after
  it performs the dump operation.



CAUTIONS
  The drvr_register_flush interface causes a system crash and displays an
  appropriate message on the console terminal if you specify an invalid bit
  in the flags argument.

  The flush interface that you register should never acquire a simple or
  complex lock. The reason for this is that on a panic, the kernel's call to
  the flush interface can cause the CPU to double panic, hang, or both if the
  callback interface tries to access locks that were taken through active
  code paths at the time of the panic. This double panic or hang of the CPU
  would result in no crash dump for diagnosis. A hang of the CPU can require
  operator intervention to restart the CPU.

RETURN VALUES
  None

SEE ALSO
  Kernel Interfaces: drvr_register_shutdown(9r)

Index for Section 9

Alphabetical listing for D

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