diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 79968e3..3db116c 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -396,11 +396,13 @@ static u32 drm_dp_i2c_functionality(struct i2c_adapter *adapter)
  * retrying the transaction as appropriate.  It is assumed that the
  * aux->transfer function does not modify anything in the msg other than the
  * reply field.
+ *
+ * Returns bytes transferred on success, or a negative error code on failure.
  */
 static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 {
 	unsigned int retry;
-	int err;
+	int ret;
 
 	/*
 	 * DP1.2 sections 2.7.7.1.5.6.1 and 2.7.7.1.6.6.1: A DP Source device
@@ -409,14 +411,14 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 	 */
 	for (retry = 0; retry < 7; retry++) {
 		mutex_lock(&aux->hw_mutex);
-		err = aux->transfer(aux, msg);
+		ret = aux->transfer(aux, msg);
 		mutex_unlock(&aux->hw_mutex);
-		if (err < 0) {
-			if (err == -EBUSY)
+		if (ret < 0) {
+			if (ret == -EBUSY)
 				continue;
 
-			DRM_DEBUG_KMS("transaction failed: %d\n", err);
-			return err;
+			DRM_DEBUG_KMS("transaction failed: %d\n", ret);
+			return ret;
 		}
 
 
@@ -457,9 +459,7 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 			 * Both native ACK and I2C ACK replies received. We
 			 * can assume the transfer was successful.
 			 */
-			if (err < msg->size)
-				return -EPROTO;
-			return 0;
+			return ret;
 
 		case DP_AUX_I2C_REPLY_NACK:
 			DRM_DEBUG_KMS("I2C nack\n");
@@ -482,14 +482,67 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 	return -EREMOTEIO;
 }
 
+/*
+ * Keep retrying drm_dp_i2c_do_msg until all data has been transferred.
+ *
+ * Returns an error code on failure, or a recommended transfer size on success.
+ */
+static int drm_dp_i2c_drain_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
+{
+	int ret;
+	struct drm_dp_aux_msg drain_msg;
+	int drain_bytes;
+
+	ret = drm_dp_i2c_do_msg(aux, msg);
+
+	if (ret == msg->size || ret <= 0)
+		return ret == 0 ? -EPROTO : ret;
+
+	/*
+	 * We had a partial reply. Drain out the rest of the bytes we
+	 * originally requested, then return the size of the partial
+	 * reply. In theory, this should match DP 1.2's desired behaviour
+	 * for I2C over AUX.
+	 */
+	DRM_DEBUG_KMS("Partial I2C reply: requested %zu bytes got %d bytes\n", msg->size, ret);
+	drain_msg = *msg;
+	drain_msg.size -= ret;
+	drain_msg.buffer += ret;
+	while (drain_msg.size != 0) {
+		drain_bytes = drm_dp_i2c_do_msg(aux, &drain_msg);
+		if (drain_bytes <= 0)
+			return drain_bytes == 0 ? -EPROTO : drain_bytes;
+		drain_msg.size -= drain_bytes;
+		drain_msg.buffer += drain_bytes;
+	}
+	return ret;
+}
+
+/*
+ * Bizlink designed DP->DVI-D Dual Link adapters require the I2C over AUX
+ * packets to be as large as possible. If not, the I2C transactions never
+ * succeed. Hence the default is maximum.
+ */
+static int dp_aux_i2c_transfer_size __read_mostly = DP_AUX_MAX_PAYLOAD_BYTES;
+module_param_named(dp_aux_i2c_transfer_size, dp_aux_i2c_transfer_size, int, 0600);
+MODULE_PARM_DESC(dp_aux_i2c_transfer_size,
+		 "Number of bytes to transfer in a single I2C over DP AUX CH message, (1-16, default 16)");
+
 static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 			   int num)
 {
 	struct drm_dp_aux *aux = adapter->algo_data;
 	unsigned int i, j;
+	int transfer_size;
 	struct drm_dp_aux_msg msg;
 	int err = 0;
 
+	if (dp_aux_i2c_transfer_size < 1 || dp_aux_i2c_transfer_size > DP_AUX_MAX_PAYLOAD_BYTES) {
+		DRM_ERROR("dp_aux_i2c_transfer_size invalid - changing from %d to %d\n",
+			  dp_aux_i2c_transfer_size, DP_AUX_MAX_PAYLOAD_BYTES);
+		dp_aux_i2c_transfer_size = DP_AUX_MAX_PAYLOAD_BYTES;
+	}
+
 	memset(&msg, 0, sizeof(msg));
 
 	for (i = 0; i < num; i++) {
@@ -507,20 +560,20 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 		err = drm_dp_i2c_do_msg(aux, &msg);
 		if (err < 0)
 			break;
-		/*
-		 * Many hardware implementations support FIFOs larger than a
-		 * single byte, but it has been empirically determined that
-		 * transferring data in larger chunks can actually lead to
-		 * decreased performance. Therefore each message is simply
-		 * transferred byte-by-byte.
+		/* We want each transaction to be as large as possible, but
+		 * we'll go to smaller sizes if the hardware gives us a
+		 * short reply.
 		 */
-		for (j = 0; j < msgs[i].len; j++) {
+		transfer_size = dp_aux_i2c_transfer_size;
+		for (j = 0; j < msgs[i].len; j += msg.size) {
 			msg.buffer = msgs[i].buf + j;
-			msg.size = 1;
+			msg.size = min((unsigned)transfer_size, msgs[i].len - j);
 
-			err = drm_dp_i2c_do_msg(aux, &msg);
-			if (err < 0)
+			transfer_size = drm_dp_i2c_drain_msg(aux, &msg);
+			if (transfer_size < 0) {
+				err = transfer_size;
 				break;
+			}
 		}
 		if (err < 0)
 			break;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 11f8c84..444d51b 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -42,6 +42,8 @@
  * 1.2 formally includes both eDP and DPI definitions.
  */
 
+#define DP_AUX_MAX_PAYLOAD_BYTES	16
+
 #define DP_AUX_I2C_WRITE		0x0
 #define DP_AUX_I2C_READ			0x1
 #define DP_AUX_I2C_STATUS		0x2
@@ -519,6 +521,9 @@ struct drm_dp_aux_msg {
  * transactions. The drm_dp_aux_register_i2c_bus() function registers an
  * I2C adapter that can be passed to drm_probe_ddc(). Upon removal, drivers
  * should call drm_dp_aux_unregister_i2c_bus() to remove the I2C adapter.
+ * The I2C adapter uses long transfers by default; if a partial response is
+ * received, the adapter will drop down to the size given by the partial
+ * response for this transaction only.
  *
  * Note that the aux helper code assumes that the .transfer() function
  * only modifies the reply field of the drm_dp_aux_msg structure.  The
