diff --git a/kernel/busses/i2c-piix4.c b/kernel/busses/i2c-piix4.c
index 349cc516..0a2b3c2d 100644
--- a/kernel/busses/i2c-piix4.c
+++ b/kernel/busses/i2c-piix4.c
@@ -214,7 +214,7 @@ int piix4_transaction(void)
   int timeout=0;
 
 #ifdef DEBUG
-  printk("piix4.o: Transaction: CNT=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, "
+  printk("piix4.o: Transaction (pre): CNT=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, "
          "DAT1=%02x\n",
          inb_p(SMBHSTCNT),inb_p(SMBHSTCMD),inb_p(SMBHSTADD),inb_p(SMBHSTDAT0),
          inb_p(SMBHSTDAT1));
@@ -293,6 +293,12 @@ s32 piix4_access(u8 addr, char read_write,
 {
   int i,len;
 
+#ifdef DEBUG
+  printk("piix4.o: Transaction (pre): CNT=%02x, CMD=%02x, ADD=%02x, "
+         "DAT0=%02x, DAT1=%02x\n",
+         inb_p(SMBHSTCNT),inb_p(SMBHSTCMD),inb_p(SMBHSTADD),inb_p(SMBHSTDAT0),
+         inb_p(SMBHSTDAT1));
+#endif
   switch(size) {
     case SMBUS_PROC_CALL:
       printk("piix4.o: SMBUS_PROC_CALL not supported!\n");
@@ -370,6 +376,12 @@ s32 piix4_access(u8 addr, char read_write,
         data->block[i] = inb_p(SMBBLKDAT);
       break;
   }
+#ifdef DEBUG
+  printk("piix4.o: Transaction (post): CNT=%02x, CMD=%02x, ADD=%02x, "
+         "DAT0=%02x, DAT1=%02x\n",
+         inb_p(SMBHSTCNT),inb_p(SMBHSTCMD),inb_p(SMBHSTADD),inb_p(SMBHSTDAT0),
+         inb_p(SMBHSTDAT1));
+#endif
   return 0;
 }
 
diff --git a/src/piix4.c b/src/piix4.c
index 349cc516..0a2b3c2d 100644
--- a/src/piix4.c
+++ b/src/piix4.c
@@ -214,7 +214,7 @@ int piix4_transaction(void)
   int timeout=0;
 
 #ifdef DEBUG
-  printk("piix4.o: Transaction: CNT=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, "
+  printk("piix4.o: Transaction (pre): CNT=%02x, CMD=%02x, ADD=%02x, DAT0=%02x, "
          "DAT1=%02x\n",
          inb_p(SMBHSTCNT),inb_p(SMBHSTCMD),inb_p(SMBHSTADD),inb_p(SMBHSTDAT0),
          inb_p(SMBHSTDAT1));
@@ -293,6 +293,12 @@ s32 piix4_access(u8 addr, char read_write,
 {
   int i,len;
 
+#ifdef DEBUG
+  printk("piix4.o: Transaction (pre): CNT=%02x, CMD=%02x, ADD=%02x, "
+         "DAT0=%02x, DAT1=%02x\n",
+         inb_p(SMBHSTCNT),inb_p(SMBHSTCMD),inb_p(SMBHSTADD),inb_p(SMBHSTDAT0),
+         inb_p(SMBHSTDAT1));
+#endif
   switch(size) {
     case SMBUS_PROC_CALL:
       printk("piix4.o: SMBUS_PROC_CALL not supported!\n");
@@ -370,6 +376,12 @@ s32 piix4_access(u8 addr, char read_write,
         data->block[i] = inb_p(SMBBLKDAT);
       break;
   }
+#ifdef DEBUG
+  printk("piix4.o: Transaction (post): CNT=%02x, CMD=%02x, ADD=%02x, "
+         "DAT0=%02x, DAT1=%02x\n",
+         inb_p(SMBHSTCNT),inb_p(SMBHSTCMD),inb_p(SMBHSTADD),inb_p(SMBHSTDAT0),
+         inb_p(SMBHSTDAT1));
+#endif
   return 0;
 }