ddi-forceattach(9P) Kernel Properties for Drivers ddi-forceattach(9P)NAME
ddi-forceattach, ddi-no-autodetach - properties controlling driver attach/detach behavior
DESCRIPTION
Solaris device drivers are attached by devfsadm(1M) and by the kernel in response to open(2) requests from applications. Drivers not cur-
rently in use can be detached when the system experiences memory pressure. The ddi-forceattach and ddi-no-autodetach properties can be used
to customize driver attach/detach behavior.
The ddi-forceattach is an integer property, to be set globally by means of the driver.conf(4) file. Drivers with this property set to 1 are
loaded and attached to all possible instances during system startup. The driver will not be auto-detached due to system memory pressure.
The ddi-no-autodetach is an integer property to be set globally by means of the driver.conf(4) file or created dynamically by the driver on
a per-instance basis with ddi_prop_update_int(9F). When this property is set to 1, the kernel will not auto-detach driver due to system
memory pressure.
Note that ddi-forceattach implies ddi-no-autodetach. Setting either property to a non-integer value or an integer value not equal to 1 pro-
duces undefined results. These properties do not prevent driver detaching in response to reconfiguration requests, such as executing com-
mands cfgadm(1M), modunload(1M), rem_drv(1M), and update_drv(1M).
SEE ALSO driver.conf(4)
Writing Device Drivers
SunOS 5.11 18 May 2001 ddi-forceattach(9P)
Check Out this Related Man Page
detach(9E) Driver Entry Points detach(9E)NAME
detach - detach or suspend a device
SYNOPSIS
#include <sys/ddi.h>
#include <sys/sunddi.h>
int prefix detach(dev_info_t dip, ddi_detach_cmd_t cmd);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI)
PARAMETERS
dip A pointer to the device's dev_info structure.
cmd Type of detach; the driver should return DDI_FAILURE if any value other than DDI_DETACH or DDI_SUSPEND is passed to it.
DESCRIPTION
The detach() function complements the attach(9E) routine.
DDI_DETACH
If cmd is set to DDI_DETACH, detach() is used to remove the state associated with a given instance of a device node prior to the removal of
that instance from the system.
The detach() function will be called once for each instance of the device for which there has been a successful attach(), once there are no
longer any opens on the device. An attached instance of a driver can be successfully detached only once. The detach() function should clean
up any per instance data initialized in attach(9E) and call kmem_free(9F) to free any heap allocations. For information on how to unregis-
ter interrupt handlers, see ddi_add_intr(9F). This should also include putting the underlying device into a quiescent state so that it will
not generate interrupts.
Drivers that set up timeout(9F) routines should ensure that they are cancelled before returning DDI_SUCCESS from detach().
If detach() determines a particular instance of the device cannot be removed when requested because of some exceptional condition, detach()
must return DDI_FAILURE, which prevents the particular device instance from being detached. This also prevents the driver from being
unloaded. A driver instance failing the detach must ensure that no per instance data or state is modified or freed that would compromise
the system or subsequent driver operation.
The system guarantees that the function will only be called for a particular dev_info node after (and not concurrently with) a successful
attach(9E) of that device. The system also guarantees that detach() will only be called when there are no outstanding open(9E) calls on the
device.
DDI_SUSPEND
The DDI_SUSPEND cmd is issued when the entire system is being suspended and power removed from it or when the system must be made quies-
cent. It will be issued only to devices which have a reg property or which export a pm-hardware-state property with the value needs-sus-
pend-resume.
If cmd is set to DDI_SUSPEND, detach() is used to suspend all activity of a device before power is (possibly) removed from the device. The
steps associated with suspension must include putting the underlying device into a quiescent state so that it will not generate interrupts
or modify or access memory. Once quiescence has been obtained, detach() can be called with outstanding open(9E) requests. It must save the
hardware state of the device to memory and block incoming or existing requests until attach() is called with DDI_RESUME.
If the device is used to store file systems, then after DDI_SUSPEND is issued, the device should still honor dump(9E) requests as this
entry point may be used by suspend-resume operation (see cpr(7)) to save state file. It must do this, however, without disturbing the saved
hardware state of the device.
If the device driver uses automatic device Power Management interfaces (driver exports pm-components(9P) property), it might need to call
pm_raise_power(9F) if the current power level is lower than required to complete the dump(9E) request.
Before returning successfully from a call to detach() with a command of DDI_SUSPEND, the driver must cancel any outstanding timeouts and
make any driver threads quiescent.
If DDI_FAILURE is returned for the DDI_SUSPEND cmd, either the operation to suspend the system or to make it quiescent will be aborted.
RETURN VALUES
DDI_SUCCESS For DDI_DETACH, the state associated with the given device was successfully removed. For DDI_SUSPEND, the driver was suc-
cessfully suspended.
DDI_FAILURE The operation failed or the request was not understood. The associated state is unchanged.
CONTEXT
This function is called from user context only.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Committed |
+-----------------------------+-----------------------------+
SEE ALSO cpr(7), pm(7D), pm(9P), pm-components(9P), attach(9E), dump(9E), open(9E), power(9E), ddi_add_intr(9F), ddi_dev_is_needed(9F),
ddi_map_regs(9F), kmem_free(9F), pm_raise_power(9F), timeout(9F)
Writing Device Drivers
SunOS 5.11 7 Dec 2003 detach(9E)