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:

       "small and bold">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 message 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  func-
	   tion, or if the driver is able to determine that device is present and accessible, but is not functioning 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 5.10							  13 August 1999					  ddi_dev_report_fault(9F)