On Fri, Jan 15, 2016 at 09:03:28AM -0800, Caleb Crome wrote:
If nobody objects, we can just set the value to 4 and be done with it.
I agree. And we may apply it only to i.MX platforms with DMA if other platform owners feel comfortable with the previous settings.
Another question: is the watermark ever going to be different than maxburst? Is there any reason to have them different?
The watermark is merely a threshold to trigger a DMA request. The only relationship with the burst size is that each burst transfer should not carry more data than the number of empty slots; FIFO under/overflow occurs otherwise. So it's just more efficient and safer to set an identical value to both of them. I don't think it will cause functional problems to set TFWM to 4 and burst size to 1 -- It just lets DMA operate in a single data transfer mode.