--- old/drivers/ata/sata_vsc.c	2007-02-04 13:44:54.000000000 -0500
+++ new/drivers/ata/sata_vsc.c	2007-02-07 09:13:17.000000000 -0500
@@ -345,6 +345,7 @@ static int __devinit vsc_sata_init_one (
 	int pci_dev_busy = 0;
 	void __iomem *mmio_base;
 	int rc;
+	u8 cls;
 
 	if (!printed_version++)
 		dev_printk(KERN_DEBUG, &pdev->dev, "version " DRV_VERSION "\n");
@@ -394,9 +395,13 @@ static int __devinit vsc_sata_init_one (
 	base = (unsigned long) mmio_base;
 
 	/*
-	 * Due to a bug in the chip, the default cache line size can't be used
+	 * Due to a bug in the chip, the default cache line size can't be
+	 * used (unless the default is non-zero).
 	 */
-	pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, 0x80);
+	pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &cls);
+	if (cls == 0x00) {
+		pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, 0x80);
+	}
 
 	probe_ent->sht = &vsc_sata_sht;
 	probe_ent->port_flags = ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |