diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 54961c0b2c73a58e2dc64313ff95a858bbb262d2..ef8b30d577bd5092484660c05a7cdd75a2c9a803 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -1289,6 +1289,39 @@ static const int *__devinit piix_init_sata_map(struct pci_dev *pdev,
 	return map;
 }
 
+static bool piix_no_sidpr(struct ata_host *host)
+{
+	struct pci_dev *pdev = to_pci_dev(host->dev);
+
+	/*
+	 * Samsung DB-P70 only has three ATA ports exposed and
+	 * curiously the unconnected first port reports link online
+	 * while not responding to SRST protocol causing excessive
+	 * detection delay.
+	 *
+	 * Unfortunately, the system doesn't carry enough DMI
+	 * information to identify the machine but does have subsystem
+	 * vendor and device set.  As it's unclear whether the
+	 * subsystem vendor/device is used only for this specific
+	 * board, the port can't be disabled solely with the
+	 * information; however, turning off SIDPR access works around
+	 * the problem.  Turn it off.
+	 *
+	 * This problem is reported in bnc#441240.
+	 *
+	 * https://bugzilla.novell.com/show_bug.cgi?id=441420
+	 */
+	if (pdev->vendor == PCI_VENDOR_ID_INTEL && pdev->device == 0x2920 &&
+	    pdev->subsystem_vendor == PCI_VENDOR_ID_SAMSUNG &&
+	    pdev->subsystem_device == 0xb049) {
+		dev_printk(KERN_WARNING, host->dev,
+			   "Samsung DB-P70 detected, disabling SIDPR\n");
+		return true;
+	}
+
+	return false;
+}
+
 static int __devinit piix_init_sidpr(struct ata_host *host)
 {
 	struct pci_dev *pdev = to_pci_dev(host->dev);
@@ -1302,6 +1335,10 @@ static int __devinit piix_init_sidpr(struct ata_host *host)
 		if (hpriv->map[i] == IDE)
 			return 0;
 
+	/* is it blacklisted? */
+	if (piix_no_sidpr(host))
+		return 0;
+
 	if (!(host->ports[0]->flags & PIIX_FLAG_SIDPR))
 		return 0;
 
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 714cb046b594200a17d096768f0d8a45f89a835a..f93dc029dfde99061b5416e66568d1658e101fe4 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -2066,6 +2066,7 @@ static int ata_bus_softreset(struct ata_port *ap, unsigned int devmask,
 	iowrite8(ap->ctl | ATA_SRST, ioaddr->ctl_addr);
 	udelay(20);	/* FIXME: flush */
 	iowrite8(ap->ctl, ioaddr->ctl_addr);
+	ap->last_ctl = ap->ctl;
 
 	/* wait the port to become ready */
 	return ata_sff_wait_after_reset(&ap->link, devmask, deadline);
@@ -2190,8 +2191,10 @@ void ata_sff_postreset(struct ata_link *link, unsigned int *classes)
 	}
 
 	/* set up device control */
-	if (ap->ioaddr.ctl_addr)
+	if (ap->ioaddr.ctl_addr) {
 		iowrite8(ap->ctl, ap->ioaddr.ctl_addr);
+		ap->last_ctl = ap->ctl;
+	}
 }
 EXPORT_SYMBOL_GPL(ata_sff_postreset);
 
@@ -2534,6 +2537,7 @@ void ata_bus_reset(struct ata_port *ap)
 	if (ap->flags & (ATA_FLAG_SATA_RESET | ATA_FLAG_SRST)) {
 		/* set up device control for ATA_FLAG_SATA_RESET */
 		iowrite8(ap->ctl, ioaddr->ctl_addr);
+		ap->last_ctl = ap->ctl;
 	}
 
 	DPRINTK("EXIT\n");
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 7007edd2d4517fed1a5b75773622cae9da003e44..74b1080d116da102d714c2168ca85f7e8c00fc0b 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -2218,12 +2218,13 @@ static irqreturn_t mv_interrupt(int irq, void *dev_instance)
 		else
 			handled = mv_host_intr(host, pending_irqs);
 	}
-	spin_unlock(&host->lock);
 
 	/* for MSI: unmask; interrupt cause bits will retrigger now */
 	if (using_msi)
 		writel(hpriv->main_irq_mask, hpriv->main_irq_mask_addr);
 
+	spin_unlock(&host->lock);
+
 	return IRQ_RETVAL(handled);
 }