ddi_dev_report_fault(9F)				   Kernel Functions for Drivers 				  ddi_dev_report_fault(9F)

NAME

       ddi_dev_report_fault - Report a hardware failure

SYNOPSIS

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

       void  ddi_dev_report_fault (dev_info_t	*dip,
	    ddi_fault_impact_t impact,	ddi_fault_location_t location,
	    const char	 *message );

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI)

PARAMETERS

       dip	    Pointer to the driver's dev_info structure to which the fault report relates. (Normally the caller's own dev_info pointer).

       impact	    One of a set of enumerated values indicating the impact of the fault on the device's ability to provide normal service.

       location     One  of  a	set  of  enumerated values indicating the location of the fault, relative to the hardware controlled by the driver
		    specified by dip.

       message	    Text of the message describing the fault being reported.

DESCRIPTION

       This function provides a standardized mechanism through which device drivers can report hardware faults.  Use of this  reporting  mechanism
       enables	systems  equipped  with a fault management system to respond to faults discovered by a driver. On a suitably equipped system, this
       might include automatic failover to an alternative device and/or scheduling replacement of the faulty hardware.

       The driver must indicate the impact of the fault being reported on its ability to provide service by passing one of  the  following  values
       for the impact parameter:

       DDI_SERVICE_LOST 	 Indicates a total loss of service. The driver is unable to implement the normal functions of its hardware.

       DDI_SERVICE_DEGRADED	 The  driver  is  unable  to  provide  normal service, but can provide a partial or degraded level of service. The
				 driver may have to make repeated attempts to perform an operation before it succeeds, or it  may  be  running	at
				 less than its configured speed. A driver may use this value to indicate that an alternative device should be used
				 if available, but that it can continue operation if no alternative exists.

       DDI_SERVICE_UNAFFECTED	 The service provided by the device is currently unaffected by the reported fault.  This  value  may  be  used	to
				 report recovered errors for predictive failure analysis.

       DDI_SERVICE_RESTORED	 The  driver has resumed normal service, following a previous report that service was lost or degraded.  This mes-
				 sage implies that any previously reported fault condition no longer exists.

       The location parameter should be one of the following values:

       DDI_DATAPATH_FAULT    The fault lies in the datapath between the driver and the device. The device may be unplugged, or a problem may exist
			     in  the bus on which the device resides.  This value is appropriate if the device is not responding to accesses, (for
			     example, the device may not be present) or if a call to ddi_check_acc_handle(9F) returns DDI_FAILURE.

       DDI_DEVICE_FAULT      The fault lies in the device controlled by the driver. This value is appropriate if the device returns an error  from
			     a	selftest  function,  or if the driver is able to determine that device is present and accessible, but is not func-
			     tioning correctly.

       DDI_EXTERNAL_FAULT    The fault is external to the device.  For example, an Ethernet driver would use this value  when  reporting  a  cable
			     fault.

			     If  a  device  returns detectably bad data during normal operation (an "impossible" value in a register or DMA status
			     area,  for  example),  the  driver  should  check	 the   associated   handle   using   ddi_check_acc_handle(9F)	or
			     ddi_check_dma_handle(9F)  before  reporting  the fault. If the fault is associated with the handle, the driver should
			     specify  DDI_DATAPATH_FAULT rather than DDI_DEVICE_FAULT. As a consequence of this call, the device's  state  may	be
			     updated to reflect the level of service currently available. See ddi_get_devstate(9F).

			     Note  that  if  a	driver	calls  ddi_get_devstate(9F)  and  discovers that its device is down, a fault should not be
			     reported- the device is down as the result of a fault that has already been reported. Additionally, a  driver  should
			     avoid   incurring	 or   reporting  additional  faults  when  the	device	is  already  known  to	be  unusable.  The
			     ddi_dev_report_fault() call should only be used to report hardware (device) problems and should not be used to report
			     purely software problems such as memory (or other resource) exhaustion.

EXAMPLES

       An  Ethernet  driver  receives  an error interrupt from its device if various fault conditions occur.  The driver must read an error status
       register to determine the nature of the fault, and report it appropriately:

	 static int
	 xx_error_intr(xx_soft_state *ssp)
	 {
	     ...
	     error_status = ddi_get32(ssp->handle, &ssp->regs->xx_err_status);
	     if (ddi_check_acc_handle(ssp->handle) != DDI_SUCCESS) {
		 ddi_dev_report_fault(ssp->dip, DDI_SERVICE_LOST,
		     DDI_DATAPATH_FAULT, "register access fault");
		 return DDI_INTR_UNCLAIMED;
	     }
	     if (ssp->error_status & XX_CABLE_FAULT) {
		 ddi_dev_report_fault(ssp->dip, DDI_SERVICE_LOST,
		     DDI_EXTERNAL_FAULT, "cable fault")
		 return DDI_INTR_CLAIMED;
	     }
	     if (ssp->error_status & XX_JABBER) {
		 ddi_dev_report_fault(ssp->dip, DDI_SERVICE_DEGRADED,
		     DDI_EXTERNAL_FAULT, "jabbering detected")
		 return DDI_INTR_CLAIMED;
	     }
	     ...
	 }

CONTEXT

       The ddi_dev_report_fault() function may be called from user, kernel, or interrupt context.

SEE ALSO

       ddi_check_acc_handle(9F), ddi_check_dma_handle(9F), ddi_get_devstate(9F)

SunOS 5.11							  13 August 1999					  ddi_dev_report_fault(9F)