PROBE(9E)							     PROBE(9E)

NAME
       probe - determine if a non-self-identifying device is present

SYNOPSIS
       #include <sys/conf.h>
       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       static intprefixprobe(dev_info_t *dip);

INTERFACE LEVEL
       Solaris	DDI  specific  (Solaris DDI). This entry point is required for
       non-self-identifying devices.  You must write it for such devices.  For
       self-identifying	 devices,   nulldev(9F)	 should	 be  specified	in the
       dev_ops(9S) structure if a probe routine is not necessary.

ARGUMENTS
       dip
	       Pointer to the device's	dev_info structure.

DESCRIPTION
       probe() determines whether the device  corresponding  to	 dip  actually
       exists  and  is a valid device for this driver. probe() is called after
       identify(9E) and before attach(9E) for a given dip.  For	 example,  the
       probe()	routine	 can  map  the device registers using ddi_map_regs(9F)
       then attempt to access the hardware using ddi_peek(9F) or  ddi_poke(9F)
       and  determine  if the device exists.  Then the device registers should
       be unmapped using ddi_unmap_regs(9F).

       To probe a device that was left powered off after the last detach(), it
       might  be necessary to power it up. If so, the driver must power up the
       device by accessing device registers directly. pm_raise_power(9F)  will
       be  not	be  available until attach(9E). The framework ensures that the
       ancestors of the node being probed and all  relevant  platform-specific
       power  management hardware is at full power at the time that probe() is
       called.

       probe() should only probe the device. It should not change any software
       state  and  should not create any software state. Device initialization
       should be done in attach(9E).

       For a self-identifying device, this entry point is not necessary.  How‐
       ever,  if a device exists in both self-identifying and non-self-identi‐
       fying forms, a probe() routine can be provided to simplify the  driver.
       ddi_dev_is_sid(9F) can then be used to determine whether	 probe() needs
       to do any work. See ddi_dev_is_sid(9F) for an example.

RETURN VALUES
       DDI_PROBE_SUCCESS
			      If the probe was successful.

       DDI_PROBE_FAILURE
			      If the probe failed.

       DDI_PROBE_DONTCARE
			      If the probe was	unsuccessful,  yet  attach(9E)
			      should still be called.

       DDI_PROBE_PARTIAL
			      If  the  instance is not present now, but may be
			      present in the future.

SEE ALSO
       attach(9E),   identify(9E),    ddi_dev_is_sid(9F),    ddi_map_regs(9F),
       ddi_peek(9F), ddi_poke(9F), nulldev(9F), dev_ops(9S)

       Writing Device Drivers

				 Nov 18, 1992			     PROBE(9E)

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