diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index f2277be..af3565d 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -53,6 +53,7 @@
 
 enum {
 	AHCI_PCI_BAR		= 5,
+	AHCI_MAX_PORTS		= 32,
 	AHCI_MAX_SG		= 168, /* hardware max is 64K */
 	AHCI_DMA_BOUNDARY	= 0xffffffff,
 	AHCI_USE_CLUSTERING	= 0,
@@ -77,8 +78,9 @@
 	RX_FIS_UNK		= 0x60, /* offset of Unknown FIS data */
 
 	board_ahci		= 0,
-	board_ahci_vt8251	= 1,
-	board_ahci_ign_iferr	= 2,
+	board_ahci_pi		= 1,
+	board_ahci_vt8251	= 2,
+	board_ahci_ign_iferr	= 3,
 
 	/* global controller registers */
 	HOST_CAP		= 0x00, /* host capabilities */
@@ -169,6 +171,7 @@
 	/* ap->flags bits */
 	AHCI_FLAG_NO_NCQ		= (1 << 24),
 	AHCI_FLAG_IGN_IRQ_IF_ERR	= (1 << 25), /* ignore IRQ_IF_ERR */
+	AHCI_FLAG_HONOR_PI		= (1 << 26), /* honor PORTS_IMPL */
 };
 
 struct ahci_cmd_hdr {
@@ -317,6 +320,16 @@
 		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
 		.port_ops	= &ahci_ops,
 	},
+	/* board_ahci_pi */
+	{
+		.sht		= &ahci_sht,
+		.flags		= ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |
+				  ATA_FLAG_MMIO | ATA_FLAG_PIO_DMA |
+				  ATA_FLAG_SKIP_D2H_BSY | AHCI_FLAG_HONOR_PI,
+		.pio_mask	= 0x1f, /* pio0-4 */
+		.udma_mask	= 0x7f, /* udma0-6 ; FIXME */
+		.port_ops	= &ahci_ops,
+	},
 	/* board_ahci_vt8251 */
 	{
 		.sht		= &ahci_sht,
@@ -353,22 +366,22 @@
 	{ PCI_VDEVICE(INTEL, 0x2682), board_ahci }, /* ESB2 */
 	{ PCI_VDEVICE(INTEL, 0x2683), board_ahci }, /* ESB2 */
 	{ PCI_VDEVICE(INTEL, 0x27c6), board_ahci }, /* ICH7-M DH */
-	{ PCI_VDEVICE(INTEL, 0x2821), board_ahci }, /* ICH8 */
-	{ PCI_VDEVICE(INTEL, 0x2822), board_ahci }, /* ICH8 */
-	{ PCI_VDEVICE(INTEL, 0x2824), board_ahci }, /* ICH8 */
-	{ PCI_VDEVICE(INTEL, 0x2829), board_ahci }, /* ICH8M */
-	{ PCI_VDEVICE(INTEL, 0x282a), board_ahci }, /* ICH8M */
-	{ PCI_VDEVICE(INTEL, 0x2922), board_ahci }, /* ICH9 */
-	{ PCI_VDEVICE(INTEL, 0x2923), board_ahci }, /* ICH9 */
-	{ PCI_VDEVICE(INTEL, 0x2924), board_ahci }, /* ICH9 */
-	{ PCI_VDEVICE(INTEL, 0x2925), board_ahci }, /* ICH9 */
-	{ PCI_VDEVICE(INTEL, 0x2927), board_ahci }, /* ICH9 */
-	{ PCI_VDEVICE(INTEL, 0x2929), board_ahci }, /* ICH9M */
-	{ PCI_VDEVICE(INTEL, 0x292a), board_ahci }, /* ICH9M */
-	{ PCI_VDEVICE(INTEL, 0x292b), board_ahci }, /* ICH9M */
-	{ PCI_VDEVICE(INTEL, 0x292f), board_ahci }, /* ICH9M */
-	{ PCI_VDEVICE(INTEL, 0x294d), board_ahci }, /* ICH9 */
-	{ PCI_VDEVICE(INTEL, 0x294e), board_ahci }, /* ICH9M */
+	{ PCI_VDEVICE(INTEL, 0x2821), board_ahci_pi }, /* ICH8 */
+	{ PCI_VDEVICE(INTEL, 0x2822), board_ahci_pi }, /* ICH8 */
+	{ PCI_VDEVICE(INTEL, 0x2824), board_ahci_pi }, /* ICH8 */
+	{ PCI_VDEVICE(INTEL, 0x2829), board_ahci_pi }, /* ICH8M */
+	{ PCI_VDEVICE(INTEL, 0x282a), board_ahci_pi }, /* ICH8M */
+	{ PCI_VDEVICE(INTEL, 0x2922), board_ahci_pi }, /* ICH9 */
+	{ PCI_VDEVICE(INTEL, 0x2923), board_ahci_pi }, /* ICH9 */
+	{ PCI_VDEVICE(INTEL, 0x2924), board_ahci_pi }, /* ICH9 */
+	{ PCI_VDEVICE(INTEL, 0x2925), board_ahci_pi }, /* ICH9 */
+	{ PCI_VDEVICE(INTEL, 0x2927), board_ahci_pi }, /* ICH9 */
+	{ PCI_VDEVICE(INTEL, 0x2929), board_ahci_pi }, /* ICH9M */
+	{ PCI_VDEVICE(INTEL, 0x292a), board_ahci_pi }, /* ICH9M */
+	{ PCI_VDEVICE(INTEL, 0x292b), board_ahci_pi }, /* ICH9M */
+	{ PCI_VDEVICE(INTEL, 0x292f), board_ahci_pi }, /* ICH9M */
+	{ PCI_VDEVICE(INTEL, 0x294d), board_ahci_pi }, /* ICH9 */
+	{ PCI_VDEVICE(INTEL, 0x294e), board_ahci_pi }, /* ICH9M */
 
 	/* JMicron */
 	{ PCI_VDEVICE(JMICRON, 0x2360), board_ahci_ign_iferr }, /* JMB360 */
@@ -691,7 +704,8 @@
 }
 
 static void ahci_init_controller(void __iomem *mmio, struct pci_dev *pdev,
-				 int n_ports, u32 cap)
+				 int n_ports, unsigned int port_flags,
+				 struct ahci_host_priv *hpriv)
 {
 	int i, rc;
 	u32 tmp;
@@ -700,13 +714,12 @@
 		void __iomem *port_mmio = ahci_port_base(mmio, i);
 		const char *emsg = NULL;
 
-#if 0 /* BIOSen initialize this incorrectly */
-		if (!(hpriv->port_map & (1 << i)))
+		if ((port_flags & AHCI_FLAG_HONOR_PI) &&
+		    !(hpriv->port_map & (1 << i)))
 			continue;
-#endif
 
 		/* make sure port is not active */
-		rc = ahci_deinit_port(port_mmio, cap, &emsg);
+		rc = ahci_deinit_port(port_mmio, hpriv->cap, &emsg);
 		if (rc)
 			dev_printk(KERN_WARNING, &pdev->dev,
 				   "%s (%d)\n", emsg, rc);
@@ -1363,7 +1376,8 @@
 		if (rc)
 			return rc;
 
-		ahci_init_controller(mmio, pdev, host->n_ports, hpriv->cap);
+		ahci_init_controller(mmio, pdev, host->n_ports,
+				     host->ports[0]->flags, hpriv);
 	}
 
 	ata_host_resume(host);
@@ -1475,7 +1489,7 @@
 	struct ahci_host_priv *hpriv = probe_ent->private_data;
 	struct pci_dev *pdev = to_pci_dev(probe_ent->dev);
 	void __iomem *mmio = probe_ent->mmio_base;
-	unsigned int i, using_dac;
+	unsigned int i, cap_n_ports, using_dac;
 	int rc;
 
 	rc = ahci_reset_controller(mmio, pdev);
@@ -1484,10 +1498,34 @@
 
 	hpriv->cap = readl(mmio + HOST_CAP);
 	hpriv->port_map = readl(mmio + HOST_PORTS_IMPL);
-	probe_ent->n_ports = ahci_nr_ports(hpriv->cap);
+	cap_n_ports = ahci_nr_ports(hpriv->cap);
 
 	VPRINTK("cap 0x%x  port_map 0x%x  n_ports %d\n",
-		hpriv->cap, hpriv->port_map, probe_ent->n_ports);
+		hpriv->cap, hpriv->port_map, cap_n_ports);
+
+	if (probe_ent->port_flags & AHCI_FLAG_HONOR_PI) {
+		unsigned int n_ports = cap_n_ports;
+		u32 port_map = hpriv->port_map;
+		int max_port = 0;
+
+		for (i = 0; i < AHCI_MAX_PORTS && n_ports; i++) {
+			if (port_map & (1 << i)) {
+				n_ports--;
+				port_map &= ~(1 << i);
+				max_port = i;
+			} else
+				probe_ent->dummy_port_mask |= 1 << i;
+		}
+
+		if (n_ports || port_map)
+			dev_printk(KERN_WARNING, &pdev->dev,
+				   "nr_ports (%u) and implemented port map "
+				   "(0x%x) don't match\n",
+				   cap_n_ports, hpriv->port_map);
+
+		probe_ent->n_ports = max_port + 1;
+	} else
+		probe_ent->n_ports = cap_n_ports;
 
 	using_dac = hpriv->cap & HOST_CAP_64;
 	if (using_dac &&
@@ -1519,7 +1557,8 @@
 	for (i = 0; i < probe_ent->n_ports; i++)
 		ahci_setup_port(&probe_ent->port[i], (unsigned long) mmio, i);
 
-	ahci_init_controller(mmio, pdev, probe_ent->n_ports, hpriv->cap);
+	ahci_init_controller(mmio, pdev, probe_ent->n_ports,
+			     probe_ent->port_flags, hpriv);
 
 	pci_set_master(pdev);