diff --git a/doc/busses/i2c-piix4 b/doc/busses/i2c-piix4
index 09a588ac..611ed9d3 100644
--- a/doc/busses/i2c-piix4
+++ b/doc/busses/i2c-piix4
@@ -23,3 +23,7 @@ it will try to enable it. THIS IS VERY DANGEROUS! If the BIOS did not
 set up a correct address for this module, you could get in big trouble
 (read: crashes, data corruption, etc.). Try this only as a last resort
 (try BIOS updates first, for example), and backup first!
+
+The PIIX4E is just an new version of the PIIX4; it is supported as well. The
+PIIX/PIIX3 does not implement an SMBus or I2C bus, so you can't use this
+driver on those mainboards.
diff --git a/doc/busses/piix4 b/doc/busses/piix4
index 09a588ac..611ed9d3 100644
--- a/doc/busses/piix4
+++ b/doc/busses/piix4
@@ -23,3 +23,7 @@ it will try to enable it. THIS IS VERY DANGEROUS! If the BIOS did not
 set up a correct address for this module, you could get in big trouble
 (read: crashes, data corruption, etc.). Try this only as a last resort
 (try BIOS updates first, for example), and backup first!
+
+The PIIX4E is just an new version of the PIIX4; it is supported as well. The
+PIIX/PIIX3 does not implement an SMBus or I2C bus, so you can't use this
+driver on those mainboards.
diff --git a/doc/useful_addresses.html b/doc/useful_addresses.html
index b330f044..caeb3855 100644
--- a/doc/useful_addresses.html
+++ b/doc/useful_addresses.html
@@ -1,4 +1,4 @@
-!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
 <HTML>
 <HEAD>
 <TITLE>I&#178C, SMBus and hardware monitoring references</TITLE>