Re: [PATCH] dmaengine: qcom-bam: fix circular buffer handling

[Andy Gross]

On Fri, Jun 14, 2019 at 03:20:12PM +0100, Srinivas Kandagatla wrote:
> For some reason arguments to most of the circular buffers
> macros are used in reverse, tail is used for head and vice versa.
> 
> This leads to bam thinking that there is an extra descriptor at the
> end and leading to retransmitting descriptor which was not scheduled
> by any driver. This happens after MAX_DESCRIPTORS (4096) are scheduled
> and done, so most of the drivers would not notice this, unless they are
> heavily using bam dma. Originally found this issue while testing
> SoundWire over SlimBus on DB845c which uses DMA very heavily for
> read/writes.
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>

Reviewed-by: Andy Gross <agross@xxxxxxxxxx>