[PATCH 00/18] dmaengine/amba-pl08x updates

[Russell King - ARM Linux]

On Fri, Jul 29, 2011 at 04:53:52PM +0530, viresh kumar wrote:
> On 07/29/2011 04:49 PM, Russell King - ARM Linux wrote:
> > Ok, so lets have the driver explicitly enforce one SG entry if peripheral
> > flow is set.  It would also be a good idea to pass not zero length, but
> > the real transfer size in the SG entry for the sake of having the API
> > know the full information about the transfer.
> 
> In my case, JPEG driver doesn't know how much data to transfer. So i have to
> send zero from there. Also, i am not sure why would peripheral needs to be
> flow controller if the peripherals driver already know how much to transfer?

If the jpeg driver doesn't know how much data will be transferred, how
can it allocate a buffer for the device to DMA into?