_verify(D2)                                              _verify(D2)


       NAME
             _verify - verify that driver supports a particular device

       SYNOPSIS
             #include <sys/confmgr.h>
             #include <sys/ddi.h>
             int prefix_verify(rm_key_t key);

          Arguments
             key     resource manager key used to refer to device instance

       DESCRIPTION
             Autoconfigurable drivers can supply an optional _verify entry
             point.  The _verify routine can be invoked by the user when
             running the DCU to check whether a specific set of
             configuration parameters are correct for a specific board.

             It is also possible for the driver writer to specify that the
             _verify routine should be invoked automatically by the DCU to
             verify configuration parameters before DCU does its
             board/driver mapping.  To specify that the _verify routine
             should be invoked automatically by the DCU, a V must appear in
             the verify field of the drivers drvmap file.  If a V appears
             in the verify field, the board/driver mapping is only done if
             the _verify routine returns 0.  The V is not intended for
             every driver and its use should be limited to very special
             cases.  The following example illustrates why some drivers may
             need to use the V flag.

             The Adaptec 1740 SCSI board can operate in either of two
             modes, standard or enhanced.  A different driver is needed
             depending on the mode of the board.  DCU does its board/driver
             mapping based on the board's id.  Since this board has a
             single id, it is impossible for DCU to assign the correct
             driver to this board without knowing the mode of the board.
             By supplying _verify routines and specifying V in the verify
             field of their drvmap files, DCU will invoke each of these
             driver's _verify routine and correctly assign a driver based
             on the return values.

             Not all drivers require a _verify routine.  Support for
             _verify routines is provided primarily for drivers that
             control ISA devices.  By providing a ``verify'' interface
             through the DCU for drivers that control ISA boards, the user
             can try different configuration parameters and get instant
             feedback.  This allows the user to determine the correct


                           Copyright 1994 Novell, Inc.               Page 1

      _verify(D2)                                              _verify(D2)


            configuration parameters for a board without rebuilding the
            kernel.

            Beyond support for ISA configuration and other ``special
            cases'' there are no other reasons to provide verify routines
            for drivers.  For a driver that only supports EISA, MCA, or
            PCI cards and has no ``special cases'' that must be dealt
            with, there is no need for a _verify routine.

         Return Values
            The _verify routine should return 0 if the configuration
            parameters are correct and the driver can support the board,
            otherwise it should return ENODEV.

      USAGE
            This routine is optional and is only valid for loadable
            autoconfigurable drivers.

            The _verify routine is called with a Resource Manager key that
            the driver uses to retrieve hardware parameters using the
            configuration manager interfaces.  For PDI drivers, the
            _verify routine should call sdi_hba_getconf(D3I) to get the
            hardware parameters for a particular board (this differs from
            using sdi_hba_autoconf(D3I) which will retrieve the hardware
            parameters for all boards supported by the driver).

            Since the _verify routine is sometimes called to test
            uncertain hardware parameters (for instance, to check user-
            supplied hardware parameters), it is important that _verify
            routines are do their checking very carefully.  Thus, it is
            best to not write to any I/O address unless absolutely
            necessary and only after all other possible read checks have
            been performed.  For instance, a driver could read all of its
            readable I/O addresses first.  If any are missing or contain
            unexpected values, it should fail.  Then, it should perform
            any necessary tests that require writing to I/O addresses.

            The _verify routine should not add new parameters to the
            Resource Manager database or change the value of existing
            parameters.

         Synchronization Constraints
            The _verify routine has user context and can sleep.





                          Copyright 1994 Novell, Inc.               Page 2

       _verify(D2)                                              _verify(D2)


       REFERENCES
             dcu(1M), cm_getval(D3), Drvmap(4), cm_params(D5), errnos(D5)

       NOTICES
          Portability
             All processors

          Applicability
             ddi: 6, 6mp, 7, 7mp







































                           Copyright 1994 Novell, Inc.               Page 3