diff --git a/drivers/scsi/aic7xxx/aic7xxx.h b/drivers/scsi/aic7xxx/aic7xxx.h
index e24e6067401bb1b674078fb24e314f9887bfb237..62ff8c3dc2bb44479b1dcf3c1fe8f100df9e0b2f 100644
--- a/drivers/scsi/aic7xxx/aic7xxx.h
+++ b/drivers/scsi/aic7xxx/aic7xxx.h
@@ -231,6 +231,7 @@ typedef enum {
 	AHC_TARGETMODE	= 0x20000,	/* Has tested target mode support */
 	AHC_MULTIROLE	= 0x40000,	/* Space for two roles at a time */
 	AHC_REMOVABLE	= 0x80000,	/* Hot-Swap supported */
+	AHC_HVD		= 0x100000,	/* HVD rather than SE */
 	AHC_AIC7770_FE	= AHC_FENONE,
 	/*
 	 * The real 7850 does not support Ultra modes, but there are
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
index eadfefdd8d7a975373c4a752ee7d3b2436d91a8b..debf3e2a079808454beb1fcf67f2670b0ed5862c 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -2537,6 +2537,22 @@ static void ahc_linux_set_iu(struct scsi_target *starget, int iu)
 }
 #endif
 
+static void ahc_linux_get_signalling(struct Scsi_Host *shost)
+{
+	struct ahc_softc *ahc = *(struct ahc_softc **)shost->hostdata;
+	u8 mode = ahc_inb(ahc, SBLKCTL);
+
+	if (mode & ENAB40)
+		spi_signalling(shost) = SPI_SIGNAL_LVD;
+	else if (mode & ENAB20)
+		spi_signalling(shost) = 
+			ahc->features & AHC_HVD ?
+			SPI_SIGNAL_HVD :
+			SPI_SIGNAL_SE;
+	else
+		spi_signalling(shost) = SPI_SIGNAL_UNKNOWN;
+}
+
 static struct spi_function_template ahc_linux_transport_functions = {
 	.set_offset	= ahc_linux_set_offset,
 	.show_offset	= 1,
@@ -2552,6 +2568,7 @@ static struct spi_function_template ahc_linux_transport_functions = {
 	.set_qas	= ahc_linux_set_qas,
 	.show_qas	= 1,
 #endif
+	.get_signalling	= ahc_linux_get_signalling,
 };
 
 
diff --git a/drivers/scsi/aic7xxx/aic7xxx_pci.c b/drivers/scsi/aic7xxx/aic7xxx_pci.c
index b1156fbd4a1a4bbd01516d62100dde6ab905585f..02fed4a02eb3bbba5fcba56cd8be45170822721c 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_pci.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_pci.c
@@ -144,16 +144,22 @@ static ahc_device_setup_t ahc_aic785X_setup;
 static ahc_device_setup_t ahc_aic7860_setup;
 static ahc_device_setup_t ahc_apa1480_setup;
 static ahc_device_setup_t ahc_aic7870_setup;
+static ahc_device_setup_t ahc_aic7870h_setup;
 static ahc_device_setup_t ahc_aha394X_setup;
+static ahc_device_setup_t ahc_aha394Xh_setup;
 static ahc_device_setup_t ahc_aha494X_setup;
+static ahc_device_setup_t ahc_aha494Xh_setup;
 static ahc_device_setup_t ahc_aha398X_setup;
 static ahc_device_setup_t ahc_aic7880_setup;
+static ahc_device_setup_t ahc_aic7880h_setup;
 static ahc_device_setup_t ahc_aha2940Pro_setup;
 static ahc_device_setup_t ahc_aha394XU_setup;
+static ahc_device_setup_t ahc_aha394XUh_setup;
 static ahc_device_setup_t ahc_aha398XU_setup;
 static ahc_device_setup_t ahc_aic7890_setup;
 static ahc_device_setup_t ahc_aic7892_setup;
 static ahc_device_setup_t ahc_aic7895_setup;
+static ahc_device_setup_t ahc_aic7895h_setup;
 static ahc_device_setup_t ahc_aic7896_setup;
 static ahc_device_setup_t ahc_aic7899_setup;
 static ahc_device_setup_t ahc_aha29160C_setup;
@@ -225,19 +231,19 @@ struct ahc_pci_identity ahc_pci_ident_table [] =
 		ID_AHA_2944,
 		ID_ALL_MASK,
 		"Adaptec 2944 SCSI adapter",
-		ahc_aic7870_setup
+		ahc_aic7870h_setup
 	},
 	{
 		ID_AHA_3944,
 		ID_ALL_MASK,
 		"Adaptec 3944 SCSI adapter",
-		ahc_aha394X_setup
+		ahc_aha394Xh_setup
 	},
 	{
 		ID_AHA_4944,
 		ID_ALL_MASK,
 		"Adaptec 4944 SCSI adapter",
-		ahc_aha494X_setup
+		ahc_aha494Xh_setup
 	},
 	/* aic7880 based controllers */
 	{
@@ -256,13 +262,13 @@ struct ahc_pci_identity ahc_pci_ident_table [] =
 		ID_AHA_2944U & ID_DEV_VENDOR_MASK,
 		ID_DEV_VENDOR_MASK,
 		"Adaptec 2944 Ultra SCSI adapter",
-		ahc_aic7880_setup
+		ahc_aic7880h_setup
 	},
 	{
 		ID_AHA_3944U & ID_DEV_VENDOR_MASK,
 		ID_DEV_VENDOR_MASK,
 		"Adaptec 3944 Ultra SCSI adapter",
-		ahc_aha394XU_setup
+		ahc_aha394XUh_setup
 	},
 	{
 		ID_AHA_398XU & ID_DEV_VENDOR_MASK,
@@ -278,7 +284,7 @@ struct ahc_pci_identity ahc_pci_ident_table [] =
 		ID_AHA_4944U & ID_DEV_VENDOR_MASK,
 		ID_DEV_VENDOR_MASK,
 		"Adaptec 4944 Ultra SCSI adapter",
-		ahc_aic7880_setup
+		ahc_aic7880h_setup
 	},
 	{
 		ID_AHA_2930U & ID_DEV_VENDOR_MASK,
@@ -414,7 +420,7 @@ struct ahc_pci_identity ahc_pci_ident_table [] =
 		ID_AHA_3944AU,
 		ID_ALL_MASK,
 		"Adaptec 3944A Ultra SCSI adapter",
-		ahc_aic7895_setup
+		ahc_aic7895h_setup
 	},
 	{
 		ID_AIC7895_ARO,
@@ -2120,6 +2126,16 @@ ahc_aic7870_setup(struct ahc_softc *ahc)
 	return (0);
 }
 
+static int
+ahc_aic7870h_setup(struct ahc_softc *ahc)
+{
+	int error = ahc_aic7870_setup(ahc);
+
+	ahc->features |= AHC_HVD;
+
+	return error;
+}
+
 static int
 ahc_aha394X_setup(struct ahc_softc *ahc)
 {
@@ -2131,6 +2147,16 @@ ahc_aha394X_setup(struct ahc_softc *ahc)
 	return (error);
 }
 
+static int
+ahc_aha394Xh_setup(struct ahc_softc *ahc)
+{
+	int error = ahc_aha394X_setup(ahc);
+
+	ahc->features |= AHC_HVD;
+
+	return error;
+}
+
 static int
 ahc_aha398X_setup(struct ahc_softc *ahc)
 {
@@ -2153,6 +2179,16 @@ ahc_aha494X_setup(struct ahc_softc *ahc)
 	return (error);
 }
 
+static int
+ahc_aha494Xh_setup(struct ahc_softc *ahc)
+{
+	int error = ahc_aha494X_setup(ahc);
+
+	ahc->features |= AHC_HVD;
+
+	return error;
+}
+
 static int
 ahc_aic7880_setup(struct ahc_softc *ahc)
 {
@@ -2174,6 +2210,17 @@ ahc_aic7880_setup(struct ahc_softc *ahc)
 	return (0);
 }
 
+static int
+ahc_aic7880h_setup(struct ahc_softc *ahc)
+{
+	int error = ahc_aic7880_setup(ahc);
+
+	ahc->features |= AHC_HVD;
+
+	return error;
+}
+
+
 static int
 ahc_aha2940Pro_setup(struct ahc_softc *ahc)
 {
@@ -2193,6 +2240,16 @@ ahc_aha394XU_setup(struct ahc_softc *ahc)
 	return (error);
 }
 
+static int
+ahc_aha394XUh_setup(struct ahc_softc *ahc)
+{
+	int error = ahc_aha394XU_setup(ahc);
+
+	ahc->features |= AHC_HVD;
+
+	return error;
+}
+
 static int
 ahc_aha398XU_setup(struct ahc_softc *ahc)
 {
@@ -2291,6 +2348,16 @@ ahc_aic7895_setup(struct ahc_softc *ahc)
 	return (0);
 }
 
+static int
+ahc_aic7895h_setup(struct ahc_softc *ahc)
+{
+	int error = ahc_aic7895_setup(ahc);
+
+	ahc->features |= AHC_HVD;
+
+	return error;
+}
+
 static int
 ahc_aic7896_setup(struct ahc_softc *ahc)
 {