--- a/usr/src/cmd/mdb/common/modules/pmcs/pmcs.c	Thu Dec 03 10:09:44 2009 -0800
+++ b/usr/src/cmd/mdb/common/modules/pmcs/pmcs.c	Thu Dec 03 13:34:01 2009 -0700
@@ -2197,7 +2197,6 @@
 	    "    -h: Print more detailed hardware information\n"
 	    "    -i: Print interrupt coalescing information\n"
 	    "    -I: Print information about each iport\n"
-	    "    -l: Dump the trace log (cannot be used with other options)\n"
 	    "    -p: Print information about each attached PHY\n"
 	    "    -q: Dump inbound queues\n"
 	    "    -Q: Dump outbound queues\n"

--- a/usr/src/uts/common/io/scsi/adapters/pmcs/pmcs.conf	Thu Dec 03 10:09:44 2009 -0800
+++ b/usr/src/uts/common/io/scsi/adapters/pmcs/pmcs.conf	Thu Dec 03 13:34:01 2009 -0700
@@ -50,7 +50,7 @@
 # 0x0010 - Debug information with regard to discovery/configuration
 # 0x0020 - Debug information with regard to iport
 # 0x0040 - Debug information with regard to map
-# 0x0080 - Report on SCSI underflow status
+# 0x0080 - Report on SCSI underruns and residuals
 # 0x0100 - Report SCSI status for every command
 # 0x0200 - PHY lock/unlock debug (very noisy)
 # 0x0400 - Debug information with regard to device state

--- a/usr/src/uts/common/io/scsi/adapters/pmcs/pmcs_scsa.c	Thu Dec 03 10:09:44 2009 -0800
+++ b/usr/src/uts/common/io/scsi/adapters/pmcs/pmcs_scsa.c	Thu Dec 03 13:34:01 2009 -0700
@@ -1989,11 +1989,43 @@
 				pmcs_latch_status(pwp, sp, rptr->status, xd,
 				    slen, pptr->path);
 			} else if (rptr->datapres == SAS_RSP_DATAPRES_NO_DATA) {
+				pmcout_ssp_comp_t *sspcp;
+				sspcp = (pmcout_ssp_comp_t *)msg;
+				uint32_t *residp;
 				/*
 				 * This is the case for a plain SCSI status.
+				 * Note: If RESC_V is set and we're here, there
+				 * is a residual.  We need to find it and update
+				 * the packet accordingly.
 				 */
 				pmcs_latch_status(pwp, sp, rptr->status, NULL,
 				    0, pptr->path);
+
+				if (sspcp->resc_v) {
+					/*
+					 * Point residual to the SSP_RESP_IU
+					 */
+					residp = (uint32_t *)(sspcp + 1);
+					/*
+					 * param contains the number of bytes
+					 * between where the SSP_RESP_IU may
+					 * or may not be and the residual.
+					 * Increment residp by the appropriate
+					 * number of words: (param+resc_pad)/4).
+					 */
+					residp += (LE_32(sspcp->param) +
+					    sspcp->resc_pad) /
+					    sizeof (uint32_t);
+					pmcs_prt(pwp, PMCS_PRT_DEBUG_UNDERFLOW,
+					    pptr, xp, "%s: tgt 0x%p "
+					    "residual %d for pkt 0x%p",
+					    __func__, (void *) xp, *residp,
+					    (void *) pkt);
+					ASSERT(LE_32(*residp) <=
+					    pkt->pkt_dma_len);
+					(void) pmcs_set_resid(pkt,
+					    pkt->pkt_dma_len, LE_32(*residp));
+				}
 			} else {
 				pmcs_print_entry(pwp, PMCS_PRT_DEBUG,
 				    "illegal SAS response", msg);

--- a/usr/src/uts/common/sys/scsi/adapters/pmcs/pmcs.h	Thu Dec 03 10:09:44 2009 -0800
+++ b/usr/src/uts/common/sys/scsi/adapters/pmcs/pmcs.h	Thu Dec 03 13:34:01 2009 -0700
@@ -49,6 +49,7 @@
 #include <sys/scsi/generic/smp_frames.h>
 #include <sys/atomic.h>
 #include <sys/byteorder.h>
+#include <sys/sysmacros.h>
 #include <sys/bitmap.h>
 #include <sys/queue.h>
 #include <sys/sdt.h>

--- a/usr/src/uts/common/sys/scsi/adapters/pmcs/pmcs_iomb.h	Thu Dec 03 10:09:44 2009 -0800
+++ b/usr/src/uts/common/sys/scsi/adapters/pmcs/pmcs_iomb.h	Thu Dec 03 13:34:01 2009 -0700
@@ -466,6 +466,45 @@
 #define	PMCOUT_STATUS_IO_ABORT_IN_PROGRESS				0x40
 
 /*
+ * IOMB formats
+ *
+ * NOTE: All IOMBs are little-endian with exceptions to certain parts of
+ * some IOMBs.  For example, the SSP_RESPONSE_IU in the SSP_COMPLETION
+ * outbound IOMB is big-endian (SAS).
+ */
+
+/* Common IOMB header */
+
+typedef struct pmcs_iomb_header {
+	uint8_t		opcode_lo;
+	DECL_BITFIELD2(opcode_hi: 4,
+	    cat			: 4);
+	DECL_BITFIELD2(obid	: 6,
+	    rsvd1		: 2);
+	DECL_BITFIELD4(buf_count: 5,
+	    rsvd2		: 1,
+	    h_bit		: 1,
+	    v_bit		: 1);
+} pmcs_iomb_header_t;
+
+/* PMCOUT_SSP_COMPLETION */
+
+typedef struct pmcout_ssp_comp {
+	pmcs_iomb_header_t	header;
+	uint32_t		htag;
+	uint32_t		status;
+	uint32_t		param;
+	uint16_t		ssp_tag;
+	DECL_BITFIELD3(resc_v	: 1,
+	    resc_pad	: 2,
+	    rsvd1	: 5);
+	uint8_t			rsvd2;
+	/* SSP_RESPONSE_IU (if it exists) */
+	/* Residual count (if resc_v is set) */
+} pmcout_ssp_comp_t;
+
+
+/*
  * Device State definitions
  */
 #define	PMCS_DEVICE_STATE_NOT_AVAILABLE		0x0	/* Unconfigured tgt */