quiesce - quiesce a device
#include <sys/ddi.h> #include <sys/sunddi.h> int prefixquiesce(dev_info_t *dip);
int ddi_quiesce_not_needed(dev_info_t *dip);
Solaris DDI specific (Solaris DDI)
A pointer to the device's dev_info structure.
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.
quiesce() returns the following:
The device has been successfully quiesced.
The operation failed.
This function is called from kernel context only.
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.