==== //depot/user/simokawa/firewire/sys/dev/dcons/dcons_crom.c#10 - /home/p4/firewire/sys/dev/dcons/dcons_crom.c ====
@@ -62,6 +62,14 @@
 
 #include <sys/cons.h>
 
+#define EXPOSE_IDT 1
+
+#if (defined(__i386__) || defined(__amd64__)) && defined(EXPOSE_IDT)
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <machine/segments.h> /* for idt */
+#endif
 static bus_addr_t dcons_paddr;
 
 #if __FreeBSD_version >= 500000
@@ -107,7 +115,23 @@
 }
 
 #ifndef NEED_NEW_DRIVER
+#define EXPOSE_IDT 1
+#if (defined(__i386__) || defined(__amd64__)) && defined(EXPOSE_IDT)
 static void
+dcons_crom_expose_idt(struct dcons_crom_softc *sc)
+{
+	static off_t idt_paddr;
+
+	/* XXX */
+	idt_paddr = (char *)idt - (char *)KERNBASE;
+
+#define DCONS_CSR_IDT_HI 0x3c
+#define DCONS_CSR_IDT_LO 0x3d
+	crom_add_entry(&sc->unit, DCONS_CSR_IDT_HI, ADDR_HI(idt_paddr));
+	crom_add_entry(&sc->unit, DCONS_CSR_IDT_LO, ADDR_LO(idt_paddr));
+}
+#endif
+static void
 dcons_crom_post_busreset(void *arg)
 {
 	struct dcons_crom_softc *sc;
@@ -127,6 +151,9 @@
 	crom_add_simple_text(src, &sc->unit, &sc->ver, "dcons");
 	crom_add_entry(&sc->unit, DCONS_CSR_KEY_HI, ADDR_HI(dcons_paddr));
 	crom_add_entry(&sc->unit, DCONS_CSR_KEY_LO, ADDR_LO(dcons_paddr));
+#if (defined(__i386__) || defined(__amd64__)) && defined(EXPOSE_IDT)
+	dcons_crom_expose_idt(sc);
+#endif
 }
 #endif
 
==== //depot/user/simokawa/firewire/usr.sbin/dconschat/dconschat.c#8 - /home/p4/firewire/usr.sbin/dconschat/dconschat.c ====
@@ -87,6 +87,7 @@
 	kvm_t *kd;
 	int kq;
 	off_t paddr;
+	off_t idt;
 #define F_READY		(1 << 1)
 #define F_RD_ONLY	(1 << 2)
 #define F_ALT_BREAK	(1 << 3)
@@ -145,6 +146,18 @@
 }
 
 static void
+dconschat_reset_target(struct dcons_state *dc)
+{
+	char zeros[PAGE_SIZE];
+	if (dc->idt == 0)
+		return;
+
+	bzero(&zeros[0], PAGE_SIZE);
+	printf("\n[dconschat reset target(idt=0x%zx)...]\r\n", dc->idt);
+	dwrite(dc, (void *)zeros, PAGE_SIZE, dc->idt);
+}
+
+static void
 dconschat_cleanup(int sig)
 {
 	struct dcons_state *dc;
@@ -154,9 +167,9 @@
 		tcsetattr(STDIN_FILENO, TCSADRAIN, &dc->tsave);
 
 	if (sig > 0)
-		printf("\n[dconschat exiting with signal %d ...]\n", sig);
+		printf("\n[dconschat exiting with signal %d ...]\r\n", sig);
 	else
-		printf("\n[dconschat exiting...]\n");
+		printf("\n[dconschat exiting...]\r\n");
 	exit(0);
 }
 
@@ -166,7 +179,7 @@
 {
 	off_t addr;
 	int i, state = 0;
-	u_int32_t buf, hi = 0, lo = 0;
+	u_int32_t buf, hi = 0, lo = 0, idt_hi = 0, idt_lo = 0;
 	struct csrreg *reg; 
 
 	reg = (struct csrreg *)&buf;
@@ -193,21 +206,35 @@
 				state = 2;
 			break;
 		case 2:
-			if (reg->key == DCONS_CSR_KEY_HI)
+			switch (reg->key) {
+			case DCONS_CSR_KEY_HI:
 				hi = reg->val;
-			else if (reg->key == DCONS_CSR_KEY_LO) {
+				break;
+			case DCONS_CSR_KEY_LO:
 				lo = reg->val;
+				break;
+			case 0x3c:
+				idt_hi = reg->val;
+				break;
+			case 0x3d:
+				idt_lo = reg->val;
 				goto out;
+				break;
+			case 0x81:
+				break;
+			default:
+				state = 0;
 			}
 			break;
 		}
 	}
-	/* not found */
-	return (-1);
 out:
 	if (verbose)
 		printf("addr: %06x %06x\n", hi, lo); 
 	dc->paddr = ((off_t)hi << 24) | lo;
+	dc->idt = ((off_t)idt_hi << 24) | idt_lo;
+	if (dc->paddr == 0)
+		return (-1);
 	return (0);
 }
 #endif
@@ -654,6 +681,8 @@
 				dc->escape_state = STATE0;
 				if (*sp == '.')
 					dconschat_cleanup(0);
+				else if (*sp == 'R')
+					dconschat_reset_target(dc);
 			}
 			if (*sp == KEY_CR)
 				dc->escape_state = STATE1;