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

illumos DDI specific (illumos 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 quiesce()
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, quiesce()
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 indicate 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

uadmin(2), reboot(8), uadmin(8), 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.

September 16, 2008 QUIESCE(9E)