Make i8042.c even less picky about detecting an AUX port because of

broken chipsets that don't support the LOOP command or report failure
on the TEST command. Hopefully this won't screw any old 386/486
systems without the AUX port.

drivers/input/serio/i8042.c

@@ -654,24 +654,26 @@ static int __init i8042_check_aux(struct i8042_values *values)
 	i8042_flush();
 
 /*
- * Internal loopback test - filters out AT-type i8042's
+ * Internal loopback test - filters out AT-type i8042's. Unfortunately
+ * SiS screwed up and their 5597 doesn't support the LOOP command even
+ * though it has an AUX port.
  */
 
 	param = 0x5a;
-	if (i8042_command(&param, I8042_CMD_AUX_LOOP) || param != 0xa5)
-		return -1;
+	if (i8042_command(&param, I8042_CMD_AUX_LOOP) || param != 0xa5) {
 
 /*
  * External connection test - filters out AT-soldered PS/2 i8042's
  * 0x00 - no error, 0x01-0x03 - clock/data stuck, 0xff - general error
  * 0xfa - no error on some notebooks which ignore the spec
- * We ignore general error, since some chips report it even under normal
- * operation.
+ * Because it's common for chipsets to return error on perfectly functioning
+ * AUX ports, we test for this only when the LOOP command failed.
  */
 
 		if (i8042_command(&param, I8042_CMD_AUX_TEST)
 		    	|| (param && param != 0xfa && param != 0xff))
 				return -1;
+	}
 
 /*
  * Bit assignment test - filters out PS/2 i8042's in AT mode