Index: share/man/man4/acpi.4
===================================================================
RCS file: /cvsroot/src/share/man/man4/acpi.4,v
retrieving revision 1.77
diff -p -r1.77 acpi.4
*** share/man/man4/acpi.4	13 Jul 2014 12:08:32 -0000	1.77
--- share/man/man4/acpi.4	8 Sep 2014 23:49:36 -0000
***************
*** 24,30 ****
  .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  .\" POSSIBILITY OF SUCH DAMAGE.
  .\"
! .Dd July 13, 2014
  .Dt ACPI 4
  .Os
  .Sh NAME
--- 24,30 ----
  .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  .\" POSSIBILITY OF SUCH DAMAGE.
  .\"
! .Dd September 8, 2014
  .Dt ACPI 4
  .Os
  .Sh NAME
***************
*** 39,44 ****
--- 39,45 ----
  .Cd options	ACPI_DSDT_OVERRIDE
  .Cd options	ACPI_DSDT_FILE=""
  .Cd options	ACPI_BLACKLIST_YEAR=2000
+ .Cd options	ACPI__DIS_IS_BROKEN
  .Sh DESCRIPTION
  .Nx
  provides machine-independent bus support for
*************** is not specified, default to
*** 97,102 ****
--- 98,110 ----
  in the build directory.
  .It Dv ACPI_BLACKLIST_YEAR=2000
  Do not use ACPI with any BIOS made on or before the specified year.
+ .It Dv ACPI__DIS_IS_BROKEN
+ Do not call the ACPI "_DIS" method to disable interrupt links.
+ This may be required on specific
+ .Dq nForce4
+ chipset systems, which hard hang when this method is called instead of
+ having it fail gracefully.
+ .Dq
  .El
  .Sh SYSCTL SUPPORT
  Few
*************** among others.
*** 658,660 ****
--- 666,672 ----
  Most of the
  .Tn ACPI
  power management functionalities are not implemented.
+ .Pp
+ The
+ .Dv ACPI__DIS_IS_BROKEN
+ option should not be necessary.
Index: sys/dev/acpi/acpi_pci_link.c
===================================================================
RCS file: /cvsroot/src/sys/dev/acpi/acpi_pci_link.c,v
retrieving revision 1.21
diff -p -r1.21 acpi_pci_link.c
*** sys/dev/acpi/acpi_pci_link.c	14 Apr 2014 01:56:18 -0000	1.21
--- sys/dev/acpi/acpi_pci_link.c	8 Sep 2014 23:49:36 -0000
*************** acpi_pci_link_attach(struct acpi_pci_lin
*** 533,543 ****
--- 533,545 ----
  	 * run _DIS (i.e., the method doesn't exist), assume the initial
  	 * IRQ was routed by the BIOS.
  	 */
+ #ifndef ACPI__DIS_IS_BROKEN
  	if (ACPI_SUCCESS(AcpiEvaluateObject(sc->pl_handle, "_DIS", NULL,
  	    NULL)))
  		for (i = 0; i < sc->pl_num_links; i++)
  			sc->pl_links[i].l_irq = PCI_INVALID_IRQ;
  	else
+ #endif
  		for (i = 0; i < sc->pl_num_links; i++)
  			if (PCI_INTERRUPT_VALID(sc->pl_links[i].l_irq))
  				sc->pl_links[i].l_routed = TRUE;
Index: sys/dev/acpi/files.acpi
===================================================================
RCS file: /cvsroot/src/sys/dev/acpi/files.acpi,v
retrieving revision 1.94
diff -p -r1.94 files.acpi
*** sys/dev/acpi/files.acpi	1 Apr 2014 17:47:36 -0000	1.94
--- sys/dev/acpi/files.acpi	8 Sep 2014 23:49:36 -0000
*************** include "dev/acpi/acpica/files.acpica"
*** 4,9 ****
--- 4,10 ----
  
  defflag	opt_acpi.h	ACPIVERBOSE ACPI_DEBUG ACPI_ACTIVATE_DEV
  			ACPI_DSDT_OVERRIDE ACPI_SCANPCI ACPI_BREAKPOINT
+ 			ACPI__DIS_IS_BROKEN
  defparam opt_acpi.h	ACPI_DSDT_FILE := "\"/dev/null\""
  defparam opt_acpi.h	ACPI_BLACKLIST_YEAR = 2000