[PATCH] libata: add 40pin "short" cable support, honour drive side speed detection

[deweerdt@free.fr: build fix]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Frederik Deweerdt <deweerdt@free.fr>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 720174d..14b726b 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -93,7 +93,7 @@
 #include <linux/libata.h>
 
 #define DRV_NAME	"ata_piix"
-#define DRV_VERSION	"2.00ac6"
+#define DRV_VERSION	"2.00ac7"
 
 enum {
 	PIIX_IOCFG		= 0x54, /* IDE I/O configuration register */
@@ -571,6 +571,23 @@
 MODULE_PARM_DESC(force_pcs, "force honoring or ignoring PCS to work around "
 		 "device mis-detection (0=default, 1=ignore PCS, 2=honor PCS)");
 
+struct ich_laptop {
+	u16 device;
+	u16 subvendor;
+	u16 subdevice;
+};
+
+/*
+ *	List of laptops that use short cables rather than 80 wire
+ */
+
+static const struct ich_laptop ich_laptop[] = {
+	/* devid, subvendor, subdev */
+	{ 0x27DF, 0x0005, 0x0280 },	/* ICH7 on Acer 5602WLMi */
+	/* end marker */
+	{ 0, }
+};
+
 /**
  *	piix_pata_cbl_detect - Probe host controller cable detect info
  *	@ap: Port for which cable detect info is desired
@@ -585,12 +602,24 @@
 static void ich_pata_cbl_detect(struct ata_port *ap)
 {
 	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	const struct ich_laptop *lap = &ich_laptop[0];
 	u8 tmp, mask;
 
 	/* no 80c support in host controller? */
 	if ((ap->udma_mask & ~ATA_UDMA_MASK_40C) == 0)
 		goto cbl40;
 
+	/* Check for specials - Acer Aspire 5602WLMi */
+	while (lap->device) {
+		if (lap->device == pdev->device &&
+		    lap->subvendor == pdev->subsystem_vendor &&
+		    lap->subdevice == pdev->subsystem_device) {
+			ap->cbl = ATA_CBL_PATA40_SHORT;
+		    	return;
+		}
+		lap++;
+	}
+
 	/* check BIOS cable detect results */
 	mask = ap->port_no == 0 ? PIIX_80C_PRI : PIIX_80C_SEC;
 	pci_read_config_byte(pdev, PIIX_IOCFG, &tmp);
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 915a55a..b896119 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3119,6 +3119,13 @@
 	 */
 	if (ap->cbl == ATA_CBL_PATA40)
 		xfer_mask &= ~(0xF8 << ATA_SHIFT_UDMA);
+	/* Apply drive side cable rule. Unknown or 80 pin cables reported
+	 * host side are checked drive side as well. Cases where we know a
+	 * 40wire cable is used safely for 80 are not checked here.
+	 */
+        if (ata_drive_40wire(dev->id) && (ap->cbl == ATA_CBL_PATA_UNK || ap->cbl == ATA_CBL_PATA80))
+		xfer_mask &= ~(0xF8 << ATA_SHIFT_UDMA);
+
 
 	xfer_mask &= ata_pack_xfermask(dev->pio_mask,
 				       dev->mwdma_mask, dev->udma_mask);
diff --git a/drivers/ata/pata_ali.c b/drivers/ata/pata_ali.c
index 64eed99..e6d2b84 100644
--- a/drivers/ata/pata_ali.c
+++ b/drivers/ata/pata_ali.c
@@ -78,7 +78,7 @@
 	   implement the detect logic */
 
 	if (ali_cable_override(pdev))
-		return ATA_CBL_PATA80;
+		return ATA_CBL_PATA40_SHORT;
 
 	/* Host view cable detect 0x4A bit 0 primary bit 1 secondary
 	   Bit set for 40 pin */