opensolaris man page for quiesce

quiesce(9E)							Driver Entry Points						       quiesce(9E)

NAME
       quiesce - quiesce a device

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

       int prefixquiesce(dev_info_t *dip);

       int ddi_quiesce_not_needed(dev_info_t *dip);

INTERFACE LEVEL
       Solaris DDI specific (Solaris DDI)

PARAMETERS
       dip    A pointer to the device's dev_info structure.

DESCRIPTION
       The  quiesce() function quiesces a device so that the device no longer generates interrupts, modifies or accesses memory. The driver should
       reset the device to a hardware state from which the device can be correctly configured by the driver's attach() routine	without  a  system
       power cycle or being configured by the firmware. For devices with a defined reset state configuration, the driver should return that device
       to that state as part of the quiesce operation. Fast Reboot, where firmware is bypassed when booting to a new OS image, is such a case.

       quiesce() is only called for an attached device instance as one of the final operations of a reboot sequence, and no other  thread  can	be
       active  for this device. The system guarantees that no other driver entry point is active or invoked while quiesce() is invoked. The system
       also guarantees that no timeout or taskq is invoked. The system is single-threaded and can not be interrupted. Therefore, the driver's qui-
       esce()  implementation must not use locks or timeouts, or rely on them being called. The driver must discard all outstanding I/O instead of
       waiting for completion. At the conclusion of the quiesce() operation, the driver must guarantee that the device no  longer  has	access	to
       memory or interrupts.

       The  only  DDI  interfaces  that  can  be  called  by  the  quiesce() implementation are non-blocking functions, such as the ddi_get*() and
       ddi_put*() functions.

       If quiesce() determines a particular instance of the device cannot be quiesced when requested because of some exceptional  condition,  qui-
       esce() returns DDI_FAILURE. This rarely happens.

       If  a  driver  has  previously  implemented  the  obsolete reset() interface, its functionality must be merged into quiesce(). The driver's
       reset() routine is no longer called if an implementation of quiesce() is present.

       ddi_quiesce_not_needed() always returns DDI_SUCCESS. A driver can set its devo_quiesce device function to ddi_quiesce_not_needed() to indi-
       cate that the device it manages does not need to be quiesced.

RETURN VALUES
       quiesce() returns the following:

       DDI_SUCCESS    The device has been successfully quiesced.

       DDI_FAILURE    The operation failed.

CONTEXT
       This function is called from kernel context only.

SEE ALSO
       reboot(1M),   uadmin(1M),   uadmin(2),  attach(9E),  detach(9E),  ddi_add_intr(9F),  ddi_map_regs(9F),  pci_config_setup(9F),  timeout(9F),
       dev_ops(9S)

NOTES
       When quiesce() is called, the system is single-threaded, therefore the driver's quiesce() implementation must not be blocked. For  example,
       the implementation must not create or tear down mappings, call FMA functions, or create or cancel callbacks.

SunOS 5.11							    16 Sep 2008 						       quiesce(9E)