ahci: sis can't do PMP

From: Piter PUNK <piterpunk@slackware.com>

SiS AHCIs say they can do PMP but can't and fail detection if SRST w/
pmp==15 is used.  Turn off PMP support.

tj: added patch description, adapted patch to #upstream-fixes and
    renamed board_ahci_sis to board_ahci_nopmp.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 29f34d0..6a4a2a2 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -90,6 +90,7 @@
 	board_ahci_mv		= 4,
 	board_ahci_sb700	= 5,
 	board_ahci_mcp65	= 6,
+	board_ahci_nopmp	= 7,
 
 	/* global controller registers */
 	HOST_CAP		= 0x00, /* host capabilities */
@@ -401,6 +402,14 @@
 		.udma_mask	= ATA_UDMA6,
 		.port_ops	= &ahci_ops,
 	},
+	/* board_ahci_nopmp */
+	{
+		AHCI_HFLAGS	(AHCI_HFLAG_NO_PMP),
+		.flags		= AHCI_FLAG_COMMON,
+		.pio_mask	= 0x1f, /* pio0-4 */
+		.udma_mask	= ATA_UDMA6,
+		.port_ops	= &ahci_ops,
+	},
 };
 
 static const struct pci_device_id ahci_pci_tbl[] = {
@@ -525,9 +534,9 @@
 	{ PCI_VDEVICE(NVIDIA, 0x0bc7), board_ahci },		/* MCP7B */
 
 	/* SiS */
-	{ PCI_VDEVICE(SI, 0x1184), board_ahci }, /* SiS 966 */
-	{ PCI_VDEVICE(SI, 0x1185), board_ahci }, /* SiS 966 */
-	{ PCI_VDEVICE(SI, 0x0186), board_ahci }, /* SiS 968 */
+	{ PCI_VDEVICE(SI, 0x1184), board_ahci_nopmp },		/* SiS 966 */
+	{ PCI_VDEVICE(SI, 0x1185), board_ahci_nopmp },		/* SiS 968 */
+	{ PCI_VDEVICE(SI, 0x0186), board_ahci_nopmp },		/* SiS 968 */
 
 	/* Marvell */
 	{ PCI_VDEVICE(MARVELL, 0x6145), board_ahci_mv },	/* 6145 */