Changes, all of them boring and minor:

1) Ugly MSFT Hyper-V workaround in ata_piix
 
 2) Fix a longstanding error recovery delay caused by excessive
    re-re-retries, when media errors occur.
 
 3) Minor hw-specific workarounds and quirks
 
 4) New PATA driver for ep93xx
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Merge tag 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev

Pull libata update from Jeff Garzik:
 "Changes, all of them boring and minor:

  1) Ugly MSFT Hyper-V workaround in ata_piix

  2) Fix a longstanding error recovery delay caused by excessive
     re-re-retries, when media errors occur.

  3) Minor hw-specific workarounds and quirks

  4) New PATA driver for ep93xx"

* tag 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  PATA host controller driver for ep93xx
  [libata] Add " 2GB ATA Flash Disk"/"ADMA428M" to DMA blacklist
  ata_generic: Skip is_intel_ider() check when ata_generic=1 is set
  libata-eh don't waste time retrying media errors (v3)
  ata_piix: defer disks to the Hyper-V drivers by default
  libata: add a host flag to ignore detected ATA devices

drivers/ata/Kconfig

@@ -416,6 +416,15 @@ config PATA_EFAR
 
 	  If unsure, say N.
 
+config PATA_EP93XX
+	tristate "Cirrus Logic EP93xx PATA support"
+	depends on ARCH_EP93XX
+	help
+	  This option enables support for the PATA controller in
+	  the Cirrus Logic EP9312 and EP9315 ARM CPU.
+
+	  If unsure, say N.
+
 config PATA_HPT366
 	tristate "HPT 366/368 PATA support"
 	depends on PCI

drivers/ata/Makefile

@@ -43,6 +43,7 @@ obj-$(CONFIG_PATA_CS5535)	+= pata_cs5535.o
 obj-$(CONFIG_PATA_CS5536)	+= pata_cs5536.o
 obj-$(CONFIG_PATA_CYPRESS)	+= pata_cypress.o
 obj-$(CONFIG_PATA_EFAR)		+= pata_efar.o
+obj-$(CONFIG_PATA_EP93XX)	+= pata_ep93xx.o
 obj-$(CONFIG_PATA_HPT366)	+= pata_hpt366.o
 obj-$(CONFIG_PATA_HPT37X)	+= pata_hpt37x.o
 obj-$(CONFIG_PATA_HPT3X2N)	+= pata_hpt3x2n.o

drivers/ata/ata_generic.c

@@ -177,7 +177,7 @@ static int ata_generic_init_one(struct pci_dev *dev, const struct pci_device_id
 	if ((id->driver_data & ATA_GEN_CLASS_MATCH) && all_generic_ide == 0)
 		return -ENODEV;
 
-	if (id->driver_data & ATA_GEN_INTEL_IDER)
+	if ((id->driver_data & ATA_GEN_INTEL_IDER) && !all_generic_ide)
 		if (!is_intel_ider(dev))
 			return -ENODEV;
 

drivers/ata/ata_piix.c

@@ -1554,6 +1554,39 @@ static bool piix_broken_system_poweroff(struct pci_dev *pdev)
 	return false;
 }
 
+static int prefer_ms_hyperv = 1;
+module_param(prefer_ms_hyperv, int, 0);
+
+static void piix_ignore_devices_quirk(struct ata_host *host)
+{
+#if IS_ENABLED(CONFIG_HYPERV_STORAGE)
+	static const struct dmi_system_id ignore_hyperv[] = {
+		{
+			/* On Hyper-V hypervisors the disks are exposed on
+			 * both the emulated SATA controller and on the
+			 * paravirtualised drivers.  The CD/DVD devices
+			 * are only exposed on the emulated controller.
+			 * Request we ignore ATA devices on this host.
+			 */
+			.ident = "Hyper-V Virtual Machine",
+			.matches = {
+				DMI_MATCH(DMI_SYS_VENDOR,
+						"Microsoft Corporation"),
+				DMI_MATCH(DMI_PRODUCT_NAME, "Virtual Machine"),
+			},
+		},
+		{ }	/* terminate list */
+	};
+	const struct dmi_system_id *dmi = dmi_first_match(ignore_hyperv);
+
+	if (dmi && prefer_ms_hyperv) {
+		host->flags |= ATA_HOST_IGNORE_ATA;
+		dev_info(host->dev, "%s detected, ATA device ignore set\n",
+			dmi->ident);
+	}
+#endif
+}
+
 /**
  *	piix_init_one - Register PIIX ATA PCI device with kernel services
  *	@pdev: PCI device to register
@@ -1669,6 +1702,9 @@ static int __devinit piix_init_one(struct pci_dev *pdev,
 	}
 	host->flags |= ATA_HOST_PARALLEL_SCAN;
 
+	/* Allow hosts to specify device types to ignore when scanning. */
+	piix_ignore_devices_quirk(host);
+
 	pci_set_master(pdev);
 	return ata_pci_sff_activate_host(host, ata_bmdma_interrupt, sht);
 }

drivers/ata/libata-core.c

@@ -1973,6 +1973,12 @@ retry:
 	if (class == ATA_DEV_ATA) {
 		if (!ata_id_is_ata(id) && !ata_id_is_cfa(id))
 			goto err_out;
+		if (ap->host->flags & ATA_HOST_IGNORE_ATA &&
+							ata_id_is_ata(id)) {
+			ata_dev_dbg(dev,
+				"host indicates ignore ATA devices, ignored\n");
+			return -ENOENT;
+		}
 	} else {
 		if (ata_id_is_ata(id))
 			goto err_out;
@@ -4051,6 +4057,7 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
 	{ "_NEC DV5800A", 	NULL,		ATA_HORKAGE_NODMA },
 	{ "SAMSUNG CD-ROM SN-124", "N001",	ATA_HORKAGE_NODMA },
 	{ "Seagate STT20000A", NULL,		ATA_HORKAGE_NODMA },
+	{ "2GB ATA Flash Disk", "ADMA428M",	ATA_HORKAGE_NODMA },
 	/* Odd clown on sil3726/4726 PMPs */
 	{ "Config  Disk",	NULL,		ATA_HORKAGE_DISABLE },
 

drivers/ata/libata-eh.c

@@ -2046,6 +2046,26 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev,
 	return action;
 }
 
+/**
+ *	ata_eh_worth_retry - analyze error and decide whether to retry
+ *	@qc: qc to possibly retry
+ *
+ *	Look at the cause of the error and decide if a retry
+ * 	might be useful or not.  We don't want to retry media errors
+ *	because the drive itself has probably already taken 10-30 seconds
+ *	doing its own internal retries before reporting the failure.
+ */
+static inline int ata_eh_worth_retry(struct ata_queued_cmd *qc)
+{
+	if (qc->flags & AC_ERR_MEDIA)
+		return 0;	/* don't retry media errors */
+	if (qc->flags & ATA_QCFLAG_IO)
+		return 1;	/* otherwise retry anything from fs stack */
+	if (qc->err_mask & AC_ERR_INVALID)
+		return 0;	/* don't retry these */
+	return qc->err_mask != AC_ERR_DEV;  /* retry if not dev error */
+}
+
 /**
  *	ata_eh_link_autopsy - analyze error and determine recovery action
  *	@link: host link to perform autopsy on
@@ -2120,9 +2140,7 @@ static void ata_eh_link_autopsy(struct ata_link *link)
 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);
 
 		/* determine whether the command is worth retrying */
-		if (qc->flags & ATA_QCFLAG_IO ||
-		    (!(qc->err_mask & AC_ERR_INVALID) &&
-		     qc->err_mask != AC_ERR_DEV))
+		if (ata_eh_worth_retry(qc))
 			qc->flags |= ATA_QCFLAG_RETRY;
 
 		/* accumulate error info */

include/linux/libata.h

@@ -247,6 +247,7 @@ enum {
 	ATA_HOST_SIMPLEX	= (1 << 0),	/* Host is simplex, one DMA channel per host only */
 	ATA_HOST_STARTED	= (1 << 1),	/* Host started */
 	ATA_HOST_PARALLEL_SCAN	= (1 << 2),	/* Ports on this host can be scanned in parallel */
+	ATA_HOST_IGNORE_ATA	= (1 << 3),	/* Ignore ATA devices on this host. */
 
 	/* bits 24:31 of host->flags are reserved for LLD specific flags */