--- //depot/projects/smpng/sys/amd64/amd64/mp_machdep.c	2011-01-14 18:03:53.000000000 0000
+++ //depot/user/jhb/ktrace/amd64/amd64/mp_machdep.c	2011-05-13 14:21:01.000000000 0000
@@ -983,13 +983,17 @@
 	/* wait for pending status end */
 	lapic_ipi_wait(-1);
 
-	/* do an INIT IPI: deassert RESET */
-	lapic_ipi_raw(APIC_DEST_ALLESELF | APIC_TRIGMOD_LEVEL |
-	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, 0);
+	if (lapic_version() < 0x14) {
+		/* do an INIT IPI: deassert RESET */
+		lapic_ipi_raw(APIC_DEST_ALLESELF | APIC_TRIGMOD_LEVEL |
+		    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, 0);
+
+		/* wait for pending status end */
+		lapic_ipi_wait(-1);
+	}
 
-	/* wait for pending status end */
-	DELAY(10000);		/* wait ~10mS */
-	lapic_ipi_wait(-1);
+	/* wait ~10mS */
+	DELAY(10000);
 
 	/*
 	 * next we do a STARTUP IPI: the previous INIT IPI might still be
--- //depot/projects/smpng/sys/amd64/include/apicvar.h	2010-09-21 20:19:24.000000000 0000
+++ //depot/user/jhb/ktrace/amd64/include/apicvar.h	2011-05-13 14:21:01.000000000 0000
@@ -227,6 +227,7 @@
 	    enum intr_trigger trigger);
 void	lapic_set_tpr(u_int vector);
 void	lapic_setup(int boot);
+int	lapic_version(void);
 
 #endif /* !LOCORE */
 #endif /* _MACHINE_APICVAR_H_ */
--- //depot/projects/smpng/sys/i386/i386/mp_machdep.c	2010-11-08 20:38:02.000000000 0000
+++ //depot/user/jhb/ktrace/i386/i386/mp_machdep.c	2011-05-13 14:21:01.000000000 0000
@@ -1086,13 +1086,17 @@
 	/* wait for pending status end */
 	lapic_ipi_wait(-1);
 
-	/* do an INIT IPI: deassert RESET */
-	lapic_ipi_raw(APIC_DEST_ALLESELF | APIC_TRIGMOD_LEVEL |
-	    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, 0);
+	if (lapic_version() < 0x14) {
+		/* do an INIT IPI: deassert RESET */
+		lapic_ipi_raw(APIC_DEST_ALLESELF | APIC_TRIGMOD_LEVEL |
+		    APIC_LEVEL_DEASSERT | APIC_DESTMODE_PHY | APIC_DELMODE_INIT, 0);
+
+		/* wait for pending status end */
+		lapic_ipi_wait(-1);
+	}
 
-	/* wait for pending status end */
-	DELAY(10000);		/* wait ~10mS */
-	lapic_ipi_wait(-1);
+	/* wait ~10mS */
+	DELAY(10000);
 
 	/*
 	 * next we do a STARTUP IPI: the previous INIT IPI might still be
--- //depot/projects/smpng/sys/i386/include/apicvar.h	2010-09-21 20:19:24.000000000 0000
+++ //depot/user/jhb/ktrace/i386/include/apicvar.h	2011-05-13 14:21:01.000000000 0000
@@ -255,6 +255,7 @@
 	    enum intr_trigger trigger);
 void	lapic_set_tpr(u_int vector);
 void	lapic_setup(int boot);
+int	lapic_version(void);
 
 #endif /* !LOCORE */
 #endif /* _MACHINE_APICVAR_H_ */
--- //depot/projects/smpng/sys/x86/x86/io_apic.c	2011-01-05 17:06:25.000000000 0000
+++ //depot/user/jhb/ktrace/x86/x86/io_apic.c	2011-05-13 14:21:01.000000000 0000
@@ -97,7 +97,6 @@
 struct ioapic {
 	struct pic io_pic;
 	u_int io_id:8;			/* logical ID */
-	u_int io_apic_id:4;
 	u_int io_intbase:8;		/* System Interrupt base */
 	u_int io_numintr:8;
 	volatile ioapic_t *io_addr;	/* XXX: should use bus_space */
@@ -528,15 +527,17 @@
 	io->io_pic = ioapic_template;
 	mtx_lock_spin(&icu_lock);
 	io->io_id = next_id++;
-	io->io_apic_id = ioapic_read(apic, IOAPIC_ID) >> APIC_ID_SHIFT;
-	if (apic_id != -1 && io->io_apic_id != apic_id) {
-		ioapic_write(apic, IOAPIC_ID, apic_id << APIC_ID_SHIFT);
-		mtx_unlock_spin(&icu_lock);
-		io->io_apic_id = apic_id;
-		printf("ioapic%u: Changing APIC ID to %d\n", io->io_id,
-		    apic_id);
-	} else
-		mtx_unlock_spin(&icu_lock);
+	if (lapic_version() < 0x14) {
+		value = ioapic_read(apic, IOAPIC_ID) >> APIC_ID_SHIFT;
+		if (apic_id != -1 && value != apic_id) {
+			ioapic_write(apic, IOAPIC_ID, apic_id << APIC_ID_SHIFT);
+			mtx_unlock_spin(&icu_lock);
+			printf("ioapic%u: Changing APIC ID to %d\n", io->io_id,
+			    apic_id);
+			mtx_lock_spin(&icu_lock);
+		}
+	}
+	mtx_unlock_spin(&icu_lock);
 	if (intbase == -1) {
 		intbase = next_ioapic_base;
 		printf("ioapic%u: Assuming intbase of %d\n", io->io_id,
--- //depot/projects/smpng/sys/x86/x86/local_apic.c	2011-01-13 17:17:59.000000000 0000
+++ //depot/user/jhb/ktrace/x86/x86/local_apic.c	2011-05-13 14:21:01.000000000 0000
@@ -318,6 +318,13 @@
 #endif
 }
 
+int
+lapic_version(void)
+{
+
+	return (lapic->version & APIC_VER_VERSION);
+}
+
 /*
  * Dump contents of local APIC registers
  */