Writing Device Drivers

Service Impact Function

A fault management capable driver must indicate whether or not an error has impacted the services provided by a device. Following detection of an error and, if necessary, a shutdown of services, the driver should invoke the ddi_fm_service_impact(9F) routine to reflect the current service state of the device instance. The service state can be used by diagnosis and recovery software to help identify or react to the problem.

The ddi_fm_service_impact() routine should be called both when an error has been detected by the driver itself, and when the framework has detected an error and marked an access or DMA handle as faulty.

void ddi_fm_service_impact(dev_info_t *dip, int svc_impact)

The following service impact values (svc_impact) are accepted by ddi_fm_service_impact():


The service provided by the device is unavailable due to a device fault or software defect.


The driver is unable to provide normal service, but the driver can provide a partial or degraded level of service. For example, the driver might have to make repeated attempts to perform an operation before it succeeds, or it might be running at less that its configured speed.


The driver has detected an error, but the services provided by the device instance are unaffected.


All of the device's services have been restored.

The call to ddi_fm_service_impact() generates the following ereports on behalf of the driver, based on the service impact argument to the service impact routine:

In the following bge code, the driver determines that it is unable to successfully restart transmitting or receiving packets as the result of an error. The service state of the device transitions to DDI_SERVICE_LOST.

 * All OK, reinitialize hardware and kick off GLD scheduling
if (bge_restart(bgep, B_TRUE) != DDI_SUCCESS) {
    (void) bge_check_acc_handle(bgep, bgep->cfg_handle);
    (void) bge_check_acc_handle(bgep, bgep->io_handle);
    ddi_fm_service_impact(bgep->devinfo, DDI_SERVICE_LOST);
    return (DDI_FAILURE);

Note –

The ddi_fm_service_impact() function should not be called from the registered callback routine.