ddi_exit_critical(9f) [sunos man page]

ddi_enter_critical(9F)					   Kernel Functions for Drivers 				    ddi_enter_critical(9F)

NAME

       ddi_enter_critical, ddi_exit_critical - enter and exit a critical region of control

SYNOPSIS

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

       unsigned int ddi_enter_critical(void);

       void ddi_exit_critical(unsignedint ddic);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI).

PARAMETERS

       ddic	       The returned value from the call to ddi_enter_critical() must be passed to ddi_exit_critical().

DESCRIPTION

       Nearly  all driver operations can be done without any special synchronization and protection mechanisms beyond those provided by, for exam-
       ple, mutexes (see mutex(9F)). However, for certain devices there can exist a very short critical region of code which must  be  allowed	to
       run  uninterrupted. The function ddi_enter_critical() provides a mechanism by which a driver can ask the system to guarantee to the best of
       its ability that the current thread of execution will neither be preempted nor interrupted. This stays in effect until a bracketing call to
       ddi_exit_critical() is made (with an argument which was the returned value from ddi_enter_critical()).

       The  driver  may  not  call  any  functions  external  to  itself  in  between the time it calls ddi_enter_critical() and the time it calls
       ddi_exit_critical().

RETURN VALUES

       ddi_enter_critical() returns an opaque unsigned integer which must be used in the subsequent call to ddi_exit_critical().

CONTEXT

       This function can be called from user or interrupt context.

WARNINGS

       Driver writers should note that in a multiple processor system  this function does not temporarily suspend other processors from executing.
       This  function  also cannot guarantee to actually block the hardware from doing such things as interrupt acknowledge cycles. What it can do
       is guarantee that the currently executing thread will not be preempted.

       Do not write code  bracketed by ddi_enter_critical() and ddi_exit_critical() that can get caught in an infinite loop, as  the  machine  may
       crash if you do.

SEE ALSO

       mutex(9F)

       Writing Device Drivers

SunOS 5.10							    4 Nov 1991						    ddi_enter_critical(9F)

ddi_intr_get_supported_types(9F)			   Kernel Functions for Drivers 			  ddi_intr_get_supported_types(9F)

NAME

       ddi_intr_get_supported_types - return information on supported hardware interrupt types

SYNOPSIS

       #include <sys/types.h>
       #include <sys/conf.h>
       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       int ddi_intr_get_supported_types(dev_info_t *dip, int *typesp);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI)

PARAMETERS

       dip	 Pointer to dev_info structure

       typesp	 Pointer to supported interrupt types

DESCRIPTION

       The ddi_intr_get_supported_types() function retrieves the interrupt types supported by a particular hardware device and by the system soft-
       ware. Upon successful return, the supported types are returned as a bit mask in	the  integer  pointed  to  by  the  typesp  argument.  See
       <sys/ddi_intr.h> for a list of interrupts that can be returned by a hardware device.

       For PCI devices that support MSI and/or MSI-X based hardware, this interface returns only the interrupt types that are supported by all the
       hardware in the path to the hardware device.

       An interrupt type is usable by the hardware device if it is returned by the ddi_intr_get_supported_types() function. The device driver  can
       be programmed to use one of the returned interrupt types to receive hardware interrupts.

RETURN VALUES

       The ddi_intr_get_supported_types() function returns:

       DDI_SUCCESS	    On success.

       DDI_EINVAL	    On encountering invalid input parameters.

       DDI_INTR_NOTFOUND    Returned when the hardware device is found not to support any hardware interrupts.

CONTEXT

       The ddi_intr_get_supported_types() function can be called from user or kernel non-interrupt context.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+

SEE ALSO

       pci(4), attributes(5), pcmcia(7D), sysbus(4), ddi_intr_add_handler(9F), ddi_intr_alloc(9F), ddi_intr_enable(9F)

       Writing Device Drivers

NOTES

       The  ddi_intr_get_supported_types()  function can be called by the device driver even at any time if the driver has added an interrupt han-
       dler for a given interrupt type.

       Soft interrupts are always usable and are not returned by this interface.

       Any consumer of this interface should verify that the return value is not equal to DDI_SUCCESS. Incomplete checking for failure codes could
       result in inconsistent behavior among platforms.

SunOS 5.11							    07 Apr 2005 				  ddi_intr_get_supported_types(9F)