Hi Jose Miguel Abreu,
	
	Thanks for the review....
Sorry for the delay in the reply please see comments inline...

quoted

 	if (chan->has_sg) {
 		dma_ctrl_write(chan, XILINX_DMA_REG_TAILDESC,
 				tail_segment->phys);
+		list_splice_tail_init(&chan->pending_list, &chan->active_list);
+		chan->desc_pendingcount = 0;
 	} else {
 		struct xilinx_vdma_tx_segment *segment, *last = NULL;
-		int i = 0;
+		int i = 0, j = 0;

 		if (chan->desc_submitcount < chan->num_frms)
 			i = chan->desc_submitcount;

-		list_for_each_entry(segment, &desc->segments, node) {
-			if (chan->ext_addr)
-				vdma_desc_write_64(chan,
-

	XILINX_VDMA_REG_START_ADDRESS_64(i++),

quoted

-					segment->hw.buf_addr,
-					segment->hw.buf_addr_msb);
-			else
-				vdma_desc_write(chan,
-

	XILINX_VDMA_REG_START_ADDRESS(i++),

quoted

-					segment->hw.buf_addr);
-
-			last = segment;
+		for (j = 0; j < chan->num_frms; ) {
+			list_for_each_entry(segment, &desc->segments, node)

{

quoted

+				if (chan->ext_addr)
+					vdma_desc_write_64(chan,
+

XILINX_VDMA_REG_START_ADDRESS_64(i++),

quoted

+					  segment->hw.buf_addr,
+					  segment->hw.buf_addr_msb);
+				else
+					vdma_desc_write(chan,
+

XILINX_VDMA_REG_START_ADDRESS(i++),

quoted

+					    segment->hw.buf_addr);
+
+				last = segment;
+			}
+			list_del(&desc->node);
+			list_add_tail(&desc->node, &chan->active_list);
+			j++;
+			if (list_empty(&chan->pending_list) ||
+			    (i == chan->num_frms))
+				break;
+			desc = list_first_entry(&chan->pending_list,
+						struct

xilinx_dma_tx_descriptor,

quoted

+						node);
 		}

 		if (!last)

@@ -1081,20 +1094,14 @@ static void xilinx_vdma_start_transfer(struct

xilinx_dma_chan *chan)

quoted

 		vdma_desc_write(chan, XILINX_DMA_REG_FRMDLY_STRIDE,
 				last->hw.stride);
 		vdma_desc_write(chan, XILINX_DMA_REG_VSIZE, last-
hw.vsize);

What if we reach here and j < num_frms? It can happen because if
the pending list is empty the loop breaks. Then VDMA will start
with framebuffers having address 0x0. You should only program
vsize when j > num_frms or when we have already previously set
the framebuffers (i.e. when submitcount has already been
incremented num_frms at least once).

In case of j < num_frms VDMA won't start the frame buffer having address 0
As we are programming the VDMA buffer address based on the desc_submitcount value only i.e. i.

Code snippet in the driver doing this:
                         list_for_each_entry(segment, &desc->segments, node) {
                                if (chan->ext_addr)
                                        vdma_desc_write_64(chan,
                                          XILINX_VDMA_REG_START_ADDRESS_64(i++),
                                          segment->hw.buf_addr,
                                          segment->hw.buf_addr_msb);
                                else
                                        vdma_desc_write(chan,
                                            XILINX_VDMA_REG_START_ADDRESS(i++),
                                            segment->hw.buf_addr);

                                last = segment;
                        } 

Initially desc_submitcount will be zero.
Let's assume h/w is configured for 10 frames and user submitted only 5 frames.
And triggered the VDMA h/w using issue_pending in this case desc_submitcount will be 5.
desc_submitcount will become zero again only when
User submits more frames than h/w capable or user submit frames up to h/w capable.

If my understanding is wrong could you please elaborate the race condition that you are talking above?
	
Regards,
Kedar.

Best regards,
Jose Miguel Abreu