port-i386/45160: 8259 PICs need to be masked when switching to IOAPIC

["Jonathan A. Kollasch" <jakllsch%kollasch.net@localhost>]

This didn't go through because I initially forgot to set the Confidential field.

>Number:         45160
>Category:       port-i386
>Synopsis:       8259 PICs need to be masked when switching to IOAPIC
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-i386-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jul 20 01:50:00 +0000 2011
>Last-Modified:  Wed Jul 20 01:52:29 +0000 2011
>Originator:     Jonathan A. Kollasch
>Release:        NetBSD 5.99.54
>Environment:
System: NetBSD trantor.kollasch.net 5.99.54 NetBSD 5.99.54 (TRANTOR) #0:
Fri Jul 8 21:51:39 CDT 2011
jakllsch%trantor.kollasch.net@localhost:/local/jakllsch/nbsd-head/build-amd64/objdir/sys/arch/amd64/compile/TRANTOR
amd64
Architecture: x86_64
Machine: amd64
>Description:
Leaving the 8259 PIC interrupts unmasked while using the IOAPIC causes
spurious interrupts that somehow lead to hardware deadlock.
>How-To-Repeat:
Run NetBSD on a recent ASUS AMD board/box.
>Fix:
Mask the 8259 PIC interrupts when switching to the IOAPIC.