Index: sys/dev/ahci/ahci.h
===================================================================
--- sys/dev/ahci/ahci.h
+++ sys/dev/ahci/ahci.h
@@ -621,6 +621,8 @@
 #define AHCI_Q_NOCCS		0x00400000
 #define AHCI_Q_NOAUX		0x00800000
 #define AHCI_Q_IOMMU_BUSWIDE	0x01000000
+#define AHCI_Q_NOSPD            0x01000000	/* Ignore SPD field in status */
+#define AHCI_Q_SLOWDEV          0x02000000	/* Device is slow in detecting drives */
 
 #define AHCI_Q_BIT_STRING	\
 	"\020"			\
@@ -648,7 +650,9 @@
 	"\026MRVL_SR_DEL"	\
 	"\027NOCCS"		\
 	"\030NOAUX"		\
-	"\031IOMMU_BUSWIDE"
+	"\031IOMMU_BUSWIDE"	\
+	"\031NOSPD"		\
+	"\032SLOWDEV"
 
 int ahci_attach(device_t dev);
 int ahci_detach(device_t dev);
Index: sys/dev/ahci/ahci.c
===================================================================
--- sys/dev/ahci/ahci.c
+++ sys/dev/ahci/ahci.c
@@ -2335,19 +2335,62 @@
 {
 	u_int32_t cmd;
 	int timeout;
+	int delay_time = 10;
+	int timeout_limit = 100000; /* 50000 */
+	int ci = -1;
+	int last_ci = 0;
+	int sact = -1;
+	int last_sact = 0;
+	int ccs = -1;
+	int last_ccs =  0;
+	int cr = 1;
+	int last_cr = 0;
 
 	/* Kill all activity on this channel */
 	cmd = ATA_INL(ch->r_mem, AHCI_P_CMD);
+	if ((cmd & AHCI_P_CMD_ST) == 0) {
+		return;
+	}
+	last_cr = ((cmd & AHCI_P_CMD_CR) != 0);
+	if (!last_cr) {
+		/* No Commands Running */
+	}
+
 	ATA_OUTL(ch->r_mem, AHCI_P_CMD, cmd & ~AHCI_P_CMD_ST);
 	/* Wait for activity stop. */
 	timeout = 0;
 	do {
-		DELAY(10);
-		if (timeout++ > 50000) {
-			device_printf(ch->dev, "stopping AHCI engine failed\n");
+		DELAY(delay_time);
+		if (++timeout >= timeout_limit) {
+			device_printf(ch->dev,
+				      "stopping AHCI engine: timeout at %d us (cr=%d, ccs=%d, ci=%d, sact=%d)\n",
+				      timeout*delay_time, cr, ccs, ci, sact);
 			break;
 		}
-	} while (ATA_INL(ch->r_mem, AHCI_P_CMD) & AHCI_P_CMD_CR);
+
+		cmd = ATA_INL(ch->r_mem, AHCI_P_CMD);
+		cr = ((cmd & AHCI_P_CMD_CR) != 0);
+		ccs = ((cmd & AHCI_P_CMD_CCS_MASK) >> AHCI_P_CMD_CCS_SHIFT);
+		
+		ci = ATA_INL(ch->r_mem, AHCI_P_CI);
+		sact = ATA_INL(ch->r_mem, AHCI_P_SACT);
+		  
+		if (cr != last_cr) {
+			last_cr = cr;
+		}
+		  
+		if (ci != last_ci) {
+			last_ci = ci;
+		}
+		  
+		  if (sact != last_sact) {
+			last_sact = sact;
+		  }
+		  
+		  if (ccs != last_ccs) {
+			last_ccs = ccs;
+		  }
+	} while (cr);
 	ch->eslots = 0;
 }
 
@@ -2606,14 +2649,26 @@
 {
 	u_int32_t status;
 	int timeout, found = 0;
-
-	/* Wait up to 100ms for "connect well" */
-	for (timeout = 0; timeout < 1000 ; timeout++) {
+	int last_status = 0;
+	int delay_time = 10; /* 10 us */
+	int timeout_full_limit   = 100000 / delay_time; /* 100ms */
+	int timeout_detect_limit =  10000 / delay_time; /*  10ms */
+	
+	for (timeout = 0; timeout < timeout_full_limit ; timeout++) {
 		status = ATA_INL(ch->r_mem, AHCI_P_SSTS);
-		if ((status & ATA_SS_DET_MASK) != ATA_SS_DET_NO_DEVICE)
+
+		if (status != last_status) {
+			last_status = status;
+		}
+		if ((status & ATA_SS_DET_MASK) != ATA_SS_DET_NO_DEVICE) {
 			found = 1;
+			/* Increase timeout to 500ms after first status change to allow for slow devices 
+			   (needed on Dell BOSS-S1 with later firmwares) */
+			if (ch->quirks & AHCI_Q_SLOWDEV)
+				timeout_full_limit = 500000 / delay_time;
+		}
 		if (((status & ATA_SS_DET_MASK) == ATA_SS_DET_PHY_ONLINE) &&
-		    ((status & ATA_SS_SPD_MASK) != ATA_SS_SPD_NO_SPEED) &&
+		    ((ch->quirks & AHCI_Q_NOSPD) || (status & ATA_SS_SPD_MASK) != ATA_SS_SPD_NO_SPEED) &&
 		    ((status & ATA_SS_IPM_MASK) == ATA_SS_IPM_ACTIVE))
 			break;
 		if ((status & ATA_SS_DET_MASK) == ATA_SS_DET_PHY_OFFLINE) {
@@ -2623,15 +2678,15 @@
 			}
 			return (0);
 		}
-		if (found == 0 && timeout >= 100)
+		if (found == 0 && timeout >= timeout_detect_limit)
 			break;
-		DELAY(100);
+		DELAY(delay_time);
 	}
-	if (timeout >= 1000 || !found) {
+	if (!found || timeout >= timeout_full_limit) {
 		if (bootverbose) {
 			device_printf(ch->dev,
-			    "SATA connect timeout time=%dus status=%08x\n",
-			    timeout * 100, status);
+				      "SATA connect timeout status 0x%08x at time=%dus\n",
+				      status, timeout * delay_time);
 		}
 		return (0);
 	}
Index: sys/dev/ahci/ahci_pci.c
===================================================================
--- sys/dev/ahci/ahci_pci.c
+++ sys/dev/ahci/ahci_pci.c
@@ -1,4 +1,4 @@
-/*-
+/*
  * Copyright (c) 2009-2012 Alexander Motin <mav@FreeBSD.org>
  * All rights reserved.
  *
@@ -291,8 +291,9 @@
 	{0x92151b4b, 0x00, "Marvell 88SE9215",  0},
 	{0x92201b4b, 0x00, "Marvell 88SE9220",  AHCI_Q_ALTSIG |
 	    AHCI_Q_IOMMU_BUSWIDE},
+	{0x92201b4b, 0x00, "Marvell 88SE9220",  AHCI_Q_ALTSIG},
 	{0x92301b4b, 0x00, "Marvell 88SE9230",  AHCI_Q_ALTSIG |
-	    AHCI_Q_IOMMU_BUSWIDE},
+	    AHCI_Q_IOMMU_BUSWIDE | AHCI_Q_SLOWDEV},
 	{0x92351b4b, 0x00, "Marvell 88SE9235",  0},
 	{0x06201103, 0x00, "HighPoint RocketRAID 620",	0},
 	{0x06201b4b, 0x00, "HighPoint RocketRAID 620",	0},