diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index b19db0f6a254..cc595eba7ba9 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -650,6 +650,11 @@ static void dummy_flush_queue_iso(struct fw_iso_context *ctx)
 {
 }
 
+static int dummy_flush_iso_completions(struct fw_iso_context *ctx)
+{
+	return -ENODEV;
+}
+
 static const struct fw_card_driver dummy_driver_template = {
 	.read_phy_reg		= dummy_read_phy_reg,
 	.update_phy_reg		= dummy_update_phy_reg,
@@ -662,6 +667,7 @@ static const struct fw_card_driver dummy_driver_template = {
 	.set_iso_channels	= dummy_set_iso_channels,
 	.queue_iso		= dummy_queue_iso,
 	.flush_queue_iso	= dummy_flush_queue_iso,
+	.flush_iso_completions	= dummy_flush_iso_completions,
 };
 
 void fw_card_release(struct kref *kref)
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 4cb27dc542ce..22c6df5f136d 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -438,6 +438,7 @@ union ioctl_arg {
 	struct fw_cdev_send_phy_packet		send_phy_packet;
 	struct fw_cdev_receive_phy_packets	receive_phy_packets;
 	struct fw_cdev_set_iso_channels		set_iso_channels;
+	struct fw_cdev_flush_iso		flush_iso;
 };
 
 static int ioctl_get_info(struct client *client, union ioctl_arg *arg)
@@ -1168,6 +1169,16 @@ static int ioctl_stop_iso(struct client *client, union ioctl_arg *arg)
 	return fw_iso_context_stop(client->iso_context);
 }
 
+static int ioctl_flush_iso(struct client *client, union ioctl_arg *arg)
+{
+	struct fw_cdev_flush_iso *a = &arg->flush_iso;
+
+	if (client->iso_context == NULL || a->handle != 0)
+		return -EINVAL;
+
+	return fw_iso_context_flush_completions(client->iso_context);
+}
+
 static int ioctl_get_cycle_timer2(struct client *client, union ioctl_arg *arg)
 {
 	struct fw_cdev_get_cycle_timer2 *a = &arg->get_cycle_timer2;
@@ -1589,6 +1600,7 @@ static int (* const ioctl_handlers[])(struct client *, union ioctl_arg *) = {
 	[0x15] = ioctl_send_phy_packet,
 	[0x16] = ioctl_receive_phy_packets,
 	[0x17] = ioctl_set_iso_channels,
+	[0x18] = ioctl_flush_iso,
 };
 
 static int dispatch_ioctl(struct client *client,
diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c
index 57c3973093ad..2f432a20ce7e 100644
--- a/drivers/firewire/core-iso.c
+++ b/drivers/firewire/core-iso.c
@@ -191,6 +191,12 @@ void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 }
 EXPORT_SYMBOL(fw_iso_context_queue_flush);
 
+int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
+{
+	return ctx->card->driver->flush_iso_completions(ctx);
+}
+EXPORT_SYMBOL(fw_iso_context_flush_completions);
+
 int fw_iso_context_stop(struct fw_iso_context *ctx)
 {
 	return ctx->card->driver->stop_iso(ctx);
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 62f57a4331e3..9047f5547d98 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -106,6 +106,8 @@ struct fw_card_driver {
 
 	void (*flush_queue_iso)(struct fw_iso_context *ctx);
 
+	int (*flush_iso_completions)(struct fw_iso_context *ctx);
+
 	int (*stop_iso)(struct fw_iso_context *ctx);
 };
 
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 632562667a01..59e7894ae3b8 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -172,6 +172,9 @@ struct iso_context {
 	struct context context;
 	void *header;
 	size_t header_length;
+	unsigned long flushing_completions;
+	u32 mc_buffer_bus;
+	u16 mc_completed;
 	u16 last_timestamp;
 	u8 sync;
 	u8 tags;
@@ -2749,28 +2752,51 @@ static int handle_ir_buffer_fill(struct context *context,
 {
 	struct iso_context *ctx =
 		container_of(context, struct iso_context, context);
+	unsigned int req_count, res_count, completed;
 	u32 buffer_dma;
 
-	if (last->res_count != 0)
+	req_count = le16_to_cpu(last->req_count);
+	res_count = le16_to_cpu(ACCESS_ONCE(last->res_count));
+	completed = req_count - res_count;
+	buffer_dma = le32_to_cpu(last->data_address);
+
+	if (completed > 0) {
+		ctx->mc_buffer_bus = buffer_dma;
+		ctx->mc_completed = completed;
+	}
+
+	if (res_count != 0)
 		/* Descriptor(s) not done yet, stop iteration */
 		return 0;
 
-	buffer_dma = le32_to_cpu(last->data_address);
 	dma_sync_single_range_for_cpu(context->ohci->card.device,
 				      buffer_dma & PAGE_MASK,
 				      buffer_dma & ~PAGE_MASK,
-				      le16_to_cpu(last->req_count),
-				      DMA_FROM_DEVICE);
+				      completed, DMA_FROM_DEVICE);
 
-	if (last->control & cpu_to_le16(DESCRIPTOR_IRQ_ALWAYS))
+	if (last->control & cpu_to_le16(DESCRIPTOR_IRQ_ALWAYS)) {
 		ctx->base.callback.mc(&ctx->base,
-				      le32_to_cpu(last->data_address) +
-				      le16_to_cpu(last->req_count),
+				      buffer_dma + completed,
 				      ctx->base.callback_data);
+		ctx->mc_completed = 0;
+	}
 
 	return 1;
 }
 
+static void flush_ir_buffer_fill(struct iso_context *ctx)
+{
+	dma_sync_single_range_for_cpu(ctx->context.ohci->card.device,
+				      ctx->mc_buffer_bus & PAGE_MASK,
+				      ctx->mc_buffer_bus & ~PAGE_MASK,
+				      ctx->mc_completed, DMA_FROM_DEVICE);
+
+	ctx->base.callback.mc(&ctx->base,
+			      ctx->mc_buffer_bus + ctx->mc_completed,
+			      ctx->base.callback_data);
+	ctx->mc_completed = 0;
+}
+
 static inline void sync_it_packet_for_cpu(struct context *context,
 					  struct descriptor *pd)
 {
@@ -2925,8 +2951,10 @@ static struct fw_iso_context *ohci_allocate_iso_context(struct fw_card *card,
 	if (ret < 0)
 		goto out_with_header;
 
-	if (type == FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL)
+	if (type == FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL) {
 		set_multichannel_mask(ohci, 0);
+		ctx->mc_completed = 0;
+	}
 
 	return &ctx->base;
 
@@ -3388,6 +3416,39 @@ static void ohci_flush_queue_iso(struct fw_iso_context *base)
 	reg_write(ctx->ohci, CONTROL_SET(ctx->regs), CONTEXT_WAKE);
 }
 
+static int ohci_flush_iso_completions(struct fw_iso_context *base)
+{
+	struct iso_context *ctx = container_of(base, struct iso_context, base);
+	int ret = 0;
+
+	tasklet_disable(&ctx->context.tasklet);
+
+	if (!test_and_set_bit_lock(0, &ctx->flushing_completions)) {
+		context_tasklet((unsigned long)&ctx->context);
+
+		switch (base->type) {
+		case FW_ISO_CONTEXT_TRANSMIT:
+		case FW_ISO_CONTEXT_RECEIVE:
+			if (ctx->header_length != 0)
+				flush_iso_completions(ctx);
+			break;
+		case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
+			if (ctx->mc_completed != 0)
+				flush_ir_buffer_fill(ctx);
+			break;
+		default:
+			ret = -ENOSYS;
+		}
+
+		clear_bit_unlock(0, &ctx->flushing_completions);
+		smp_mb__after_clear_bit();
+	}
+
+	tasklet_enable(&ctx->context.tasklet);
+
+	return ret;
+}
+
 static const struct fw_card_driver ohci_driver = {
 	.enable			= ohci_enable,
 	.read_phy_reg		= ohci_read_phy_reg,
@@ -3405,6 +3466,7 @@ static const struct fw_card_driver ohci_driver = {
 	.set_iso_channels	= ohci_set_iso_channels,
 	.queue_iso		= ohci_queue_iso,
 	.flush_queue_iso	= ohci_flush_queue_iso,
+	.flush_iso_completions	= ohci_flush_iso_completions,
 	.start_iso		= ohci_start_iso,
 	.stop_iso		= ohci_stop_iso,
 };
diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h
index b9bd349c6930..d50036953497 100644
--- a/include/linux/firewire-cdev.h
+++ b/include/linux/firewire-cdev.h
@@ -212,10 +212,11 @@ struct fw_cdev_event_request2 {
  * @header:	Stripped headers, if any
  *
  * This event is sent when the controller has completed an &fw_cdev_iso_packet
- * with the %FW_CDEV_ISO_INTERRUPT bit set, or when there have been so many
- * completed packets without the interrupt bit set that the kernel's internal
- * buffer for @header is about to overflow.  (In the latter case, kernels with
- * ABI version < 5 drop header data up to the next interrupt packet.)
+ * with the %FW_CDEV_ISO_INTERRUPT bit set, when explicitly requested with
+ * %FW_CDEV_IOC_FLUSH_ISO, or when there have been so many completed packets
+ * without the interrupt bit set that the kernel's internal buffer for @header
+ * is about to overflow.  (In the last case, kernels with ABI version < 5 drop
+ * header data up to the next interrupt packet.)
  *
  * Isochronous transmit events (context type %FW_CDEV_ISO_CONTEXT_TRANSMIT):
  *
@@ -271,7 +272,8 @@ struct fw_cdev_event_iso_interrupt {
  * This event is sent in multichannel contexts (context type
  * %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL) for &fw_cdev_iso_packet buffer
  * chunks that have been completely filled and that have the
- * %FW_CDEV_ISO_INTERRUPT bit set.
+ * %FW_CDEV_ISO_INTERRUPT bit set, or when explicitly requested with
+ * %FW_CDEV_IOC_FLUSH_ISO.
  *
  * The buffer is continuously filled with the following data, per packet:
  *  - the 1394 iso packet header as described at &fw_cdev_event_iso_interrupt,
@@ -421,6 +423,9 @@ union fw_cdev_event {
 #define FW_CDEV_IOC_RECEIVE_PHY_PACKETS _IOW('#', 0x16, struct fw_cdev_receive_phy_packets)
 #define FW_CDEV_IOC_SET_ISO_CHANNELS    _IOW('#', 0x17, struct fw_cdev_set_iso_channels)
 
+/* available since kernel version 3.4 */
+#define FW_CDEV_IOC_FLUSH_ISO           _IOW('#', 0x18, struct fw_cdev_flush_iso)
+
 /*
  * ABI version history
  *  1  (2.6.22)  - initial version
@@ -445,6 +450,7 @@ union fw_cdev_event {
  *                 %FW_CDEV_IOC_SET_ISO_CHANNELS
  *  5  (3.4)     - send %FW_CDEV_EVENT_ISO_INTERRUPT events when needed to
  *                 avoid dropping data
+ *               - added %FW_CDEV_IOC_FLUSH_ISO
  */
 
 /**
@@ -854,6 +860,25 @@ struct fw_cdev_stop_iso {
 	__u32 handle;
 };
 
+/**
+ * struct fw_cdev_flush_iso - flush completed iso packets
+ * @handle:	handle of isochronous context to flush
+ *
+ * For %FW_CDEV_ISO_CONTEXT_TRANSMIT or %FW_CDEV_ISO_CONTEXT_RECEIVE contexts,
+ * report any completed packets.
+ *
+ * For %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL contexts, report the current
+ * offset in the receive buffer, if it has changed; this is typically in the
+ * middle of some buffer chunk.
+ *
+ * Any %FW_CDEV_EVENT_ISO_INTERRUPT or %FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL
+ * events generated by this ioctl are sent synchronously, i.e., are available
+ * for reading from the file descriptor when this ioctl returns.
+ */
+struct fw_cdev_flush_iso {
+	__u32 handle;
+};
+
 /**
  * struct fw_cdev_get_cycle_timer - read cycle timer register
  * @local_time:   system time, in microseconds since the Epoch
diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index ab5b7a18decf..cdc9b719e9c7 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -426,6 +426,7 @@ int fw_iso_context_queue(struct fw_iso_context *ctx,
 			 struct fw_iso_buffer *buffer,
 			 unsigned long payload);
 void fw_iso_context_queue_flush(struct fw_iso_context *ctx);
+int fw_iso_context_flush_completions(struct fw_iso_context *ctx);
 int fw_iso_context_start(struct fw_iso_context *ctx,
 			 int cycle, int sync, int tags);
 int fw_iso_context_stop(struct fw_iso_context *ctx);