5 files changed, 30 insertions, 5 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_fs.c b/drivers/infiniband/hw/ipath/ipath_fs.c
index ebd5c7bd2cd..40cf1bc90d7 100644
--- a/drivers/infiniband/hw/ipath/ipath_fs.c
+++ b/drivers/infiniband/hw/ipath/ipath_fs.c
@@ -257,9 +257,14 @@ static ssize_t atomic_port_info_read(struct file *file, char __user *buf,
 		/* Notimpl InitType (actually, an SMA decision) */
 		/* VLHighLimit is 0 (only one VL) */
 		; /* VLArbitrationHighCap is 0 (only one VL) */
+	/*
+	 * Note: the chips support a maximum MTU of 4096, but the driver
+	 * hasn't implemented this feature yet, so set the maximum
+	 * to 2048.
+	 */
 	portinfo[10] = 	/* VLArbitrationLowCap is 0 (only one VL) */
 		/* InitTypeReply is SMA decision */
-		(5 << 16)	/* MTUCap 4096 */
+		(4 << 16)	/* MTUCap 2048 */
 		| (7 << 13)	/* VLStallCount */
 		| (0x1f << 8)	/* HOQLife */
 		| (1 << 4)
diff --git a/drivers/infiniband/hw/ipath/ipath_init_chip.c b/drivers/infiniband/hw/ipath/ipath_init_chip.c
index ee839346a3a..bdfda622174 100644
--- a/drivers/infiniband/hw/ipath/ipath_init_chip.c
+++ b/drivers/infiniband/hw/ipath/ipath_init_chip.c
@@ -310,7 +310,12 @@ static int init_chip_first(struct ipath_devdata *dd,
 	val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_sendpiosize);
 	dd->ipath_piosize2k = val & ~0U;
 	dd->ipath_piosize4k = val >> 32;
-	dd->ipath_ibmtu = 4096;	/* default to largest legal MTU */
+	/*
+	 * Note: the chips support a maximum MTU of 4096, but the driver
+	 * hasn't implemented this feature yet, so set the initial value
+	 * to 2048.
+	 */
+	dd->ipath_ibmtu = 2048;
 	val = ipath_read_kreg64(dd, dd->ipath_kregs->kr_sendpiobufcnt);
 	dd->ipath_piobcnt2k = val & ~0U;
 	dd->ipath_piobcnt4k = val >> 32;
diff --git a/drivers/infiniband/hw/ipath/ipath_mad.c b/drivers/infiniband/hw/ipath/ipath_mad.c
index 25908b02fbe..2e9e161bfd0 100644
--- a/drivers/infiniband/hw/ipath/ipath_mad.c
+++ b/drivers/infiniband/hw/ipath/ipath_mad.c
@@ -292,7 +292,12 @@ static int recv_subn_get_portinfo(struct ib_smp *smp,
 	/* pip->vl_arb_high_cap; // only one VL */
 	/* pip->vl_arb_low_cap; // only one VL */
 	/* InitTypeReply = 0 */
-	pip->inittypereply_mtucap = IB_MTU_4096;
+	/*
+	 * Note: the chips support a maximum MTU of 4096, but the driver
+	 * hasn't implemented this feature yet, so set the maximum value
+	 * to 2048.
+	 */
+	pip->inittypereply_mtucap = IB_MTU_2048;
 	// HCAs ignore VLStallCount and HOQLife
 	/* pip->vlstallcnt_hoqlife; */
 	pip->operationalvl_pei_peo_fpi_fpo = 0x10;	/* OVLs = 1 */
diff --git a/drivers/infiniband/hw/ipath/ipath_qp.c b/drivers/infiniband/hw/ipath/ipath_qp.c
index bfef08ecd34..9e07abba8aa 100644
--- a/drivers/infiniband/hw/ipath/ipath_qp.c
+++ b/drivers/infiniband/hw/ipath/ipath_qp.c
@@ -507,8 +507,13 @@ int ipath_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 		    attr->port_num > ibqp->device->phys_port_cnt)
 			goto inval;
 
+	/*
+	 * Note: the chips support a maximum MTU of 4096, but the driver
+	 * hasn't implemented this feature yet, so don't allow Path MTU
+	 * values greater than 2048.
+	 */
 	if (attr_mask & IB_QP_PATH_MTU)
-		if (attr->path_mtu > IB_MTU_4096)
+		if (attr->path_mtu > IB_MTU_2048)
 			goto inval;
 
 	if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC)
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.c b/drivers/infiniband/hw/ipath/ipath_verbs.c
index bb70845279b..980b64add32 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.c
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.c
@@ -1051,7 +1051,12 @@ static int ipath_query_port(struct ib_device *ibdev,
 	props->max_vl_num = 1;		/* VLCap = VL0 */
 	props->init_type_reply = 0;
 
-	props->max_mtu = IB_MTU_4096;
+	/*
+	 * Note: the chips support a maximum MTU of 4096, but the driver
+	 * hasn't implemented this feature yet, so set the maximum value
+	 * to 2048.
+	 */
+	props->max_mtu = IB_MTU_2048;
 	switch (dev->dd->ipath_ibmtu) {
 	case 4096:
 		mtu = IB_MTU_4096;