On Mon, Jul 25, 2011 at 04:18:04PM +0530, Vinod Koul wrote:

On Mon, 2011-07-25 at 11:36 +0100, Russell King - ARM Linux wrote:

quoted

On Mon, Jul 25, 2011 at 07:31:45PM +0900, Boojin Kim wrote:

quoted

quoted

On Mon, Jul 25, 2011 at 10:28:22AM +0900, Boojin Kim wrote:

quoted

+static void pl330_tasklet_cyclic(unsigned long data)
+{
+	struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data;
+	struct dma_pl330_desc *desc, *_dt;
+	unsigned long flags;
+	LIST_HEAD(list);
+
+	spin_lock_irqsave(&pch->lock, flags);

...

quoted

+			callback = desc->txd.callback;
+			if (callback)
+				callback(desc->txd.callback_param);

On this again - what if the callback wants to terminate the DMA activity
because there's no more audio data to be sent/received from the device?

Do you mean what is happened if the callback() is called after channel is
terminated ?
Or What is happened if Callback() calls 'dma_release_channel()' to terminate
DMA?

No.  I mean what if the callback wants to call dmaengine_terminate_all().

you are supposed to drop the lock here, that way callback can call any
DMA API, otherwise it will result in deadlock.
This make me wonder you haven't read the documentation at all, please
ensure you have read Documentation/dmaengine.txt before next posting

I know that very well thank you.  Please look at my previous post in the
previous round of patches, and the response from Boojin Kim to see why
I used this as an *EXAMPLE* to get this fixed.