[quote] DMA engine in Linux Kernel

It's where the original changes were discussed

https://lkml.org/lkml/2011/5/24/227

 

It's where the specific questions were answered about tx_submit() and device_issue_pending()

http://www.gossamer-threads.com/lists/linux/kernel/1408064?search_string=tx_submit;#1408064

they were:

 

tx_submit is not supposed to start the transfer, it is supposed to add the descriptors in dma driver's queue.

The issue_pending is supposed to actually start the transfer.

The reasons were well articulated is discussion we had  when we did the DMA documentation.
Pls see https://lkml.org/lkml/2011/5/24/530