svn commit: r269989 - head/sys/amd64/vmm/io

[Neel Natu]

Author: neel
Date: Thu Aug 14 18:03:38 2014
New Revision: 269989
URL: http://svnweb.freebsd.org/changeset/base/269989

Log:
  Reword comment to match the interrupt mode names from the MPtable spec.
  
  Reviewed by:	tychon

Modified:
  head/sys/amd64/vmm/io/vatpic.c

Modified: head/sys/amd64/vmm/io/vatpic.c
==============================================================================
--- head/sys/amd64/vmm/io/vatpic.c	Thu Aug 14 17:31:04 2014	(r269988)
+++ head/sys/amd64/vmm/io/vatpic.c	Thu Aug 14 18:03:38 2014	(r269989)
@@ -195,26 +195,29 @@ vatpic_notify_intr(struct vatpic *vatpic
 		    atpic->mask, atpic->request, atpic->service);
 
 		/*
+		 * From Section 3.6.2, "Interrupt Modes", in the
+		 * MPtable Specification, Version 1.4
+		 *
 		 * PIC interrupts are routed to both the Local APIC
 		 * and the I/O APIC to support operation in 1 of 3
 		 * modes.
 		 *
 		 * 1. Legacy PIC Mode: the PIC effectively bypasses
-		 * all APIC components.  In mode '1' the local APIC is
+		 * all APIC components.  In this mode the local APIC is
 		 * disabled and LINT0 is reconfigured as INTR to
 		 * deliver the PIC interrupt directly to the CPU.
 		 *
 		 * 2. Virtual Wire Mode: the APIC is treated as a
 		 * virtual wire which delivers interrupts from the PIC
-		 * to the CPU.  In mode '2' LINT0 is programmed as
+		 * to the CPU.  In this mode LINT0 is programmed as
 		 * ExtINT to indicate that the PIC is the source of
 		 * the interrupt.
 		 *
-		 * 3. Symmetric I/O Mode: PIC interrupts are fielded
-		 * by the I/O APIC and delivered to the appropriate
-		 * CPU.  In mode '3' the I/O APIC input 0 is
-		 * programmed as ExtINT to indicate that the PIC is
-		 * the source of the interrupt.
+		 * 3. Virtual Wire Mode via I/O APIC: PIC interrupts are
+		 * fielded by the I/O APIC and delivered to the appropriate
+		 * CPU.  In this mode the I/O APIC input 0 is programmed
+		 * as ExtINT to indicate that the PIC is the source of the
+		 * interrupt.
 		 */
 		atpic->intr_raised = true;
 		lapic_set_local_intr(vatpic->vm, -1, APIC_LVT_LINT0);