diff --git a/kernel/busses/i2c-hydra.c b/kernel/busses/i2c-hydra.c
index 0d1bd0ec..db81d4ef 100644
--- a/kernel/busses/i2c-hydra.c
+++ b/kernel/busses/i2c-hydra.c
@@ -78,6 +78,7 @@ static void bit_hydra_setscl(void *data, int state)
 		val |= HYDRA_SCLK_OE;
 	}
 	pdregw(val);
+	pdregr();	/* flush posted write */
 }
 
 static void bit_hydra_setsda(void *data, int state)
@@ -90,6 +91,7 @@ static void bit_hydra_setsda(void *data, int state)
 		val |= HYDRA_SDAT_OE;
 	}
 	pdregw(val);
+	pdregr();	/* flush posted write */
 }
 
 static int bit_hydra_getscl(void *data)
diff --git a/kernel/busses/i2c-i810.c b/kernel/busses/i2c-i810.c
index 6834077f..2e660d3c 100644
--- a/kernel/busses/i2c-i810.c
+++ b/kernel/busses/i2c-i810.c
@@ -129,12 +129,14 @@ static void bit_i810i2c_setscl(void *data, int val)
 {
 	outlong((val ? SCL_VAL_OUT : 0) | SCL_DIR | SCL_DIR_MASK | SCL_VAL_MASK,
 	     I810_GPIOB);
+	readlong(I810_GPIOB);	/* flush posted write */
 }
 
 static void bit_i810i2c_setsda(void *data, int val)
 {
  	outlong((val ? SDA_VAL_OUT : 0) | SDA_DIR | SDA_DIR_MASK | SDA_VAL_MASK,
 	     I810_GPIOB);
+	readlong(I810_GPIOB);	/* flush posted write */
 }
 
 /* The GPIO pins are open drain, so the pins always remain outputs.
@@ -161,12 +163,14 @@ static void bit_i810ddc_setscl(void *data, int val)
 {
 	outlong((val ? SCL_VAL_OUT : 0) | SCL_DIR | SCL_DIR_MASK | SCL_VAL_MASK,
 	     I810_GPIOA);
+	readlong(I810_GPIOA);	/* flush posted write */
 }
 
 static void bit_i810ddc_setsda(void *data, int val)
 {
  	outlong((val ? SDA_VAL_OUT : 0) | SDA_DIR | SDA_DIR_MASK | SDA_VAL_MASK,
 	     I810_GPIOA);
+	readlong(I810_GPIOA);	/* flush posted write */
 }
 
 static int bit_i810ddc_getscl(void *data)
@@ -236,10 +240,12 @@ void config_i810(struct pci_dev *dev)
 	cadr += I810_IOCONTROL_OFFSET;
 	cadr &= PCI_BASE_ADDRESS_MEM_MASK;
 	mem = ioremap_nocache(cadr, 0x1000);
-	bit_i810i2c_setscl(NULL, 1);
-	bit_i810i2c_setsda(NULL, 1);
-	bit_i810ddc_setscl(NULL, 1);
-	bit_i810ddc_setsda(NULL, 1);
+	if(mem) {
+		bit_i810i2c_setscl(NULL, 1);
+		bit_i810i2c_setsda(NULL, 1);
+		bit_i810ddc_setscl(NULL, 1);
+		bit_i810ddc_setsda(NULL, 1);
+	}
 }
 
 /* Detect whether a supported device can be found,
@@ -253,6 +259,8 @@ static int i810i2c_setup(void)
 		if ((dev = pci_find_device(PCI_VENDOR_ID_INTEL,
 					   *num++, dev))) {
 			config_i810(dev);
+			if(!mem)
+				return -ENOMEM;
 			printk("i2c-i810.o: i810/i815 found.\n");
 			return 0;
 		}
diff --git a/kernel/busses/i2c-savage4.c b/kernel/busses/i2c-savage4.c
index 9ebd23a5..8fb2e28c 100644
--- a/kernel/busses/i2c-savage4.c
+++ b/kernel/busses/i2c-savage4.c
@@ -122,6 +122,7 @@ static void bit_savi2c_setscl(void *data, int val)
 	else
 		r &= ~I2C_SCL_OUT;
 	outlong(r);
+	readlong();	/* flush posted write */
 }
 
 static void bit_savi2c_setsda(void *data, int val)
@@ -133,6 +134,7 @@ static void bit_savi2c_setsda(void *data, int val)
 	else
 		r &= ~I2C_SDA_OUT;
 	outlong(r);
+	readlong();	/* flush posted write */
 }
 
 /* The GPIO pins are open drain, so the pins always remain outputs.
@@ -235,10 +237,11 @@ void config_s4(struct pci_dev *dev)
 #endif
 	cadr &= PCI_BASE_ADDRESS_MEM_MASK;
 	mem = ioremap_nocache(cadr, 0x0080000);
-
-//	*((unsigned int *) (mem + REG2)) = 0x8160;
-	*((unsigned int *) (mem + REG)) = 0x00000020;
-	printk("i2c-savage4: Using Savage4 at 0x%p\n", mem);
+	if(mem) {
+//		*((unsigned int *) (mem + REG2)) = 0x8160;
+		*((unsigned int *) (mem + REG)) = 0x00000020;
+		printk("i2c-savage4: Using Savage4 at 0x%p\n", mem);
+	}
 }
 
 /* Detect chip and initialize it. */
@@ -272,6 +275,8 @@ static int savage4_setup(void)
 	} while (dev);
 
 	if (s4_num > 0) {
+		if(!mem)
+			return -ENOMEM;
 		printk("i2c-savage4: %d Savage4 found.\n", s4_num);
 		if (s4_num > 1)
 			printk("i2c-savage4: warning: only 1 supported.\n");
diff --git a/kernel/busses/i2c-voodoo3.c b/kernel/busses/i2c-voodoo3.c
index 59375567..a226641a 100644
--- a/kernel/busses/i2c-voodoo3.c
+++ b/kernel/busses/i2c-voodoo3.c
@@ -115,6 +115,7 @@ static void bit_vooi2c_setscl(void *data, int val)
 	else
 		r &= ~I2C_SCL_OUT;
 	outlong(r);
+	readlong();	/* flush posted write */
 }
 
 static void bit_vooi2c_setsda(void *data, int val)
@@ -126,6 +127,7 @@ static void bit_vooi2c_setsda(void *data, int val)
 	else
 		r &= ~I2C_SDA_OUT;
 	outlong(r);
+	readlong();	/* flush posted write */
 }
 
 /* The GPIO pins are open drain, so the pins always remain outputs.
@@ -151,6 +153,7 @@ static void bit_vooddc_setscl(void *data, int val)
 	else
 		r &= ~DDC_SCL_OUT;
 	outlong(r);
+	readlong();	/* flush posted write */
 }
 
 static void bit_vooddc_setsda(void *data, int val)
@@ -162,6 +165,7 @@ static void bit_vooddc_setsda(void *data, int val)
 	else
 		r &= ~DDC_SDA_OUT;
 	outlong(r);
+	readlong();	/* flush posted write */
 }
 
 static int bit_vooddc_getscl(void *data)
@@ -228,10 +232,11 @@ void config_v3(struct pci_dev *dev)
 #endif
 	cadr &= PCI_BASE_ADDRESS_MEM_MASK;
 	mem = ioremap_nocache(cadr, 0x1000);
-
-	*((unsigned int *) (mem + REG2)) = 0x8160;
-	*((unsigned int *) (mem + REG)) = 0xcffc0020;
-	printk("i2c-voodoo3: Using Banshee/Voodoo3 at 0x%p\n", mem);
+	if(mem) {
+		*((unsigned int *) (mem + REG2)) = 0x8160;
+		*((unsigned int *) (mem + REG)) = 0xcffc0020;
+		printk("i2c-voodoo3: Using Banshee/Voodoo3 at 0x%p\n", mem);
+	}
 }
 
 /* Detect whether a Voodoo3 or a Banshee can be found,
@@ -266,6 +271,8 @@ static int voodoo3_setup(void)
 	} while (dev);
 
 	if (v3_num > 0) {
+		if(!mem)
+			return -ENOMEM;
 		printk("i2c-voodoo3: %d Banshee/Voodoo3 found.\n", v3_num);
 		if (v3_num > 1)
 			printk("i2c-voodoo3: warning: only 1 supported.\n");