diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 32979fee618673f2dd827ba52e4e9086786b0d81..73994e2ac2cb73e3636042945511735bbb17a13f 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -565,7 +565,8 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 	/* 
 	 * If SCSI-2 or lower, store the LUN value in cmnd.
 	 */
-	if (cmd->device->scsi_level <= SCSI_2) {
+	if (cmd->device->scsi_level <= SCSI_2 &&
+	    cmd->device->scsi_level != SCSI_UNKNOWN) {
 		cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
 			       (cmd->device->lun << 5 & 0xe0);
 	}
diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index 84c3937ae8fb506c491fb23bcb23828c5d5eb9db..c750d3399a97835bbf774a6a2ab5e3dece5f330f 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -132,7 +132,9 @@ static struct {
 	{"CMD", "CRA-7280", NULL, BLIST_SPARSELUN},	/* CMD RAID Controller */
 	{"CNSI", "G7324", NULL, BLIST_SPARSELUN},	/* Chaparral G7324 RAID */
 	{"CNSi", "G8324", NULL, BLIST_SPARSELUN},	/* Chaparral G8324 RAID */
-	{"COMPAQ", "LOGICAL VOLUME", NULL, BLIST_FORCELUN},
+	{"COMPAQ", "ARRAY CONTROLLER", NULL, BLIST_SPARSELUN | BLIST_LARGELUN |
+		BLIST_MAX_512 | BLIST_REPORTLUN2},	/* Compaq RA4x00 */
+	{"COMPAQ", "LOGICAL VOLUME", NULL, BLIST_FORCELUN | BLIST_MAX_512}, /* Compaq RA4x00 */
 	{"COMPAQ", "CR3500", NULL, BLIST_FORCELUN},
 	{"COMPAQ", "MSA1000", NULL, BLIST_SPARSELUN | BLIST_NOSTARTONADD},
 	{"COMPAQ", "MSA1000 VOLUME", NULL, BLIST_SPARSELUN | BLIST_NOSTARTONADD},
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index f14945996ede5ec514bc0e390b506ffcfaa4d461..1a5474bd11a19d0eb32f434d2556ee64b1bb3c52 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -673,6 +673,7 @@ static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
 	case TYPE_MEDIUM_CHANGER:
 	case TYPE_ENCLOSURE:
 	case TYPE_COMM:
+	case TYPE_RAID:
 	case TYPE_RBC:
 		sdev->writeable = 1;
 		break;
@@ -737,6 +738,13 @@ static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
 	if (*bflags & BLIST_SELECT_NO_ATN)
 		sdev->select_no_atn = 1;
 
+	/*
+	 * Maximum 512 sector transfer length
+	 * broken RA4x00 Compaq Disk Array
+	 */
+	if (*bflags & BLIST_MAX_512)
+		blk_queue_max_sectors(sdev->request_queue, 512);
+
 	/*
 	 * Some devices may not want to have a start command automatically
 	 * issued when a device is added.
@@ -1123,10 +1131,13 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
 	 * support more than 8 LUNs.
 	 */
-	if ((bflags & BLIST_NOREPORTLUN) || 
-	     starget->scsi_level < SCSI_2 ||
-	    (starget->scsi_level < SCSI_3 && 
-	     (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8)) )
+	if (bflags & BLIST_NOREPORTLUN)
+		return 1;
+	if (starget->scsi_level < SCSI_2 &&
+	    starget->scsi_level != SCSI_UNKNOWN)
+		return 1;
+	if (starget->scsi_level < SCSI_3 &&
+	    (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8))
 		return 1;
 	if (bflags & BLIST_NOLUN)
 		return 0;
diff --git a/include/scsi/scsi_devinfo.h b/include/scsi/scsi_devinfo.h
index 174101b2069bb086b8419ffab9635f0bd8c5cd78..d31b16d25a09f0c0980f7ce824a890a70c86f605 100644
--- a/include/scsi/scsi_devinfo.h
+++ b/include/scsi/scsi_devinfo.h
@@ -28,4 +28,5 @@
 #define BLIST_NO_ULD_ATTACH	0x100000 /* device is actually for RAID config */
 #define BLIST_SELECT_NO_ATN	0x200000 /* select without ATN */
 #define BLIST_RETRY_HWERROR	0x400000 /* retry HARDWARE_ERROR */
+#define BLIST_MAX_512		0x800000 /* maximum 512 sector cdb length */
 #endif