DDI_FM_HANDLER_REGISTER(9F) Kernel Functions for Drivers


ddi_fm_handler_register, ddi_fm_handler_unregister - register or
unregister an error handling callback


#include <sys/ddifm.h>

void ddi_fm_handler_register(dev_info_t *dip,
ddi_err_func_t error_handler, void *impl_data);

void ddi_fm_handler_unregister(dev_info_t *dip);


illumos DDI specific (illumos DDI)


Pointer to the dev_info structure

Pointer to an error handler callback function

Pointer to private data for use by the caller


The ddi_fm_handler_register() function registers an error handler
callback routine with the I/O Fault Management framework. The error
handler callback, error_handler, is called to process error conditions
detected by the system. In addition to its device instance, dip, the
error handler is called with a pointer to a fault management error status
structure, ddi_fm_error_t. For example:

int (*ddi_err_func_t)(dev_info_t *dip, ddi_fm_error_t *error_status);

A driver error handling callback is passed the following arguments:

o a pointer to the device instance registered for this callback.

o a data structure containing common fault management data and
status for error handling.

The primary responsibilities of the error handler include:

o to check for outstanding hardware or software errors.

o where possible, to isolate the device that might have caused
the errors.

o to report errors that were detected.

During the invocation of an error handler, a device driver might need to
quiesce or suspend all I/O activities in order to check for error
conditions or status in:

o hardware control and status registers.

o outstanding I/O transactions.

o access or DMA handles.

For each error detected, the driver must formulate and post an error
report via ddi_fm_ereport_post() for problem analysis by the illumos
Fault Manager fmd(8).

For a PCI, PCI/X, or PCI Express leaf device, the pci_ereport_post()
function is provided to carry out reporting responsibilities on behalf of
the driver. In many cases, an error handler callback function of the
following form can be used:

xxx_err_cb(dev_info_t *dip, ddi_fm_error_t *errp) {
pci_ereport_post(dip, errp, NULL);
return (errp->fme_status);

In addition, the driver might be able to carry out further device
specific checks within the error handler.

Error handlers can be called from kernel, interrupt, or high-level
interrupt context. The interrupt block cookie returned from ddi_fm_init()
should be used to allocate and initialize any synchronization variables
and locks that might be used within the error handler callback function.
Such locks may not be held by the driver when a device register is
accessed with functions such as ddi_get8(9F) and ddi_put8(9F).

The data structure, ddi_fm_error_t, contains an FMA protocol (format 1)
ENA for the current error propagation chain, the status of the error
handler callback, an error expectation flag, and any potential access or
DMA handles associated with an error detected by the parent nexus.

The ddi_fm_handler_unregister() function removes a previously registered
error handling callback for the device instance specified by the dip.


The ddi_fm_handler_register() and ddi_fm_handler_unregister() functions
must be called from kernel context in an attach(9E) or detach(9E) entry
point. The registered error handler, error_handler, callback can be
called from kernel, interrupt, or high level interrupt context.


See attributes(7) for descriptions of the following attributes:

|Interface Stability | Committed |


attributes(7), fmd(8), attach(9E), detach(9E), ddi_fm_ereport_post(9F),
ddi_fm_init(9F), ddi_get8(9F), ddi_put8(9F), pci_ereport_post(9F),

Writing Device Drivers

illumos May 14, 2007 DDI_FM_HANDLER_REGISTER(9F)