diff --git a/drivers/ide/pci/aec62xx.c b/drivers/ide/pci/aec62xx.c
index ca16f37..7f46c22 100644
--- a/drivers/ide/pci/aec62xx.c
+++ b/drivers/ide/pci/aec62xx.c
@@ -140,7 +140,7 @@
 
 static unsigned int __devinit init_chipset_aec62xx(struct pci_dev *dev, const char *name)
 {
-	int bus_speed = system_bus_clock();
+	int bus_speed = ide_pci_clk ? ide_pci_clk : system_bus_clock();
 
 	if (bus_speed <= 33)
 		pci_set_drvdata(dev, (void *) aec6xxx_33_base);
diff --git a/drivers/ide/pci/alim15x3.c b/drivers/ide/pci/alim15x3.c
index b5a3bc3..075dcf9 100644
--- a/drivers/ide/pci/alim15x3.c
+++ b/drivers/ide/pci/alim15x3.c
@@ -294,7 +294,7 @@
 	int s_time, a_time, c_time;
 	u8 s_clc, a_clc, r_clc;
 	unsigned long flags;
-	int bus_speed = system_bus_clock();
+	int bus_speed = ide_pci_clk ? ide_pci_clk : system_bus_clock();
 	int port = hwif->channel ? 0x5c : 0x58;
 	int portFIFO = hwif->channel ? 0x55 : 0x54;
 	u8 cd_dma_fifo = 0;
diff --git a/drivers/ide/pci/amd74xx.c b/drivers/ide/pci/amd74xx.c
index f7c8838..efcf543 100644
--- a/drivers/ide/pci/amd74xx.c
+++ b/drivers/ide/pci/amd74xx.c
@@ -179,7 +179,7 @@
  * Determine the system bus clock.
  */
 
-	amd_clock = system_bus_clock() * 1000;
+	amd_clock = (ide_pci_clk ? ide_pci_clk : system_bus_clock()) * 1000;
 
 	switch (amd_clock) {
 		case 33000: amd_clock = 33333; break;
diff --git a/drivers/ide/pci/cmd640.c b/drivers/ide/pci/cmd640.c
index 0f6f11e6..6e7a6fa 100644
--- a/drivers/ide/pci/cmd640.c
+++ b/drivers/ide/pci/cmd640.c
@@ -552,7 +552,14 @@
 {
 	int setup_time, active_time, recovery_time, clock_time;
 	u8 setup_count, active_count, recovery_count, recovery_count2, cycle_count;
-	int bus_speed = system_bus_clock();
+	int bus_speed;
+
+	if (cmd640_vlb && ide_vlb_clk)
+		bus_speed = ide_vlb_clk;
+	else if (!cmd640_vlb && ide_pci_clk)
+		bus_speed = ide_pci_clk;
+	else
+		bus_speed = system_bus_clock();
 
 	if (pio_mode > 5)
 		pio_mode = 5;
diff --git a/drivers/ide/pci/cmd64x.c b/drivers/ide/pci/cmd64x.c
index 006fb62..0867471 100644
--- a/drivers/ide/pci/cmd64x.c
+++ b/drivers/ide/pci/cmd64x.c
@@ -68,8 +68,8 @@
  */
 static void program_cycle_times (ide_drive_t *drive, int cycle_time, int active_time)
 {
-	struct pci_dev *dev	= to_pci_dev(drive->hwif->dev);
-	int clock_time		= 1000 / system_bus_clock();
+	struct pci_dev *dev = to_pci_dev(drive->hwif->dev);
+	int clock_time = 1000 / (ide_pci_clk ? ide_pci_clk : system_bus_clock());
 	u8  cycle_count, active_count, recovery_count, drwtim;
 	static const u8 recovery_values[] =
 		{15, 15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0};
@@ -128,7 +128,7 @@
 			    ide_pio_timings[pio].active_time);
 
 	setup_count = quantize_timing(ide_pio_timings[pio].setup_time,
-				      1000 / system_bus_clock());
+			1000 / (ide_pci_clk ? ide_pci_clk : system_bus_clock()));
 
 	/*
 	 * The primary channel has individual address setup timing registers
diff --git a/drivers/ide/pci/cy82c693.c b/drivers/ide/pci/cy82c693.c
index e30eae5..8ef551a 100644
--- a/drivers/ide/pci/cy82c693.c
+++ b/drivers/ide/pci/cy82c693.c
@@ -136,7 +136,7 @@
 static void compute_clocks(u8 pio, pio_clocks_t *p_pclk)
 {
 	int clk1, clk2;
-	int bus_speed = system_bus_clock();	/* get speed of PCI bus */
+	int bus_speed = ide_pci_clk ? ide_pci_clk : system_bus_clock();
 
 	/* we don't check against CY82C693's min and max speed,
 	 * so you can play with the idebus=xx parameter
diff --git a/drivers/ide/pci/opti621.c b/drivers/ide/pci/opti621.c
index 9edacba..f766be9 100644
--- a/drivers/ide/pci/opti621.c
+++ b/drivers/ide/pci/opti621.c
@@ -210,7 +210,7 @@
 {
 	if (pio != PIO_NOT_EXIST) {
 		int adr_setup, data_pls;
-		int bus_speed = system_bus_clock();
+		int bus_speed = ide_pci_clk ? ide_pci_clk : system_bus_clock();
 
 		adr_setup = ide_pio_timings[pio].setup_time;
 		data_pls = ide_pio_timings[pio].active_time;
diff --git a/drivers/ide/pci/via82cxxx.c b/drivers/ide/pci/via82cxxx.c
index bbd17be..566e0ec 100644
--- a/drivers/ide/pci/via82cxxx.c
+++ b/drivers/ide/pci/via82cxxx.c
@@ -340,7 +340,7 @@
 	 * Determine system bus clock.
 	 */
 
-	via_clock = system_bus_clock() * 1000;
+	via_clock = (ide_pci_clk ? ide_pci_clk : system_bus_clock()) * 1000;
 
 	switch (via_clock) {
 		case 33000: via_clock = 33333; break;