Hello Vinod, On 14/05/17 15:33, Alexander Sverdlin wrote: >>> + if (m2p_channel_nextbuf(edmac) != 0) >>> + dev_warn(chan2dev(edmac), "M2P: Starting from BASE1\n"); >> But then you are actually not restarting from BASE1 as you reset, so the >> warn is wrong.. Perhaps a more meaningful msg would be to say "expected 0 >> but found 1, so resetting" Should it be something like "M2P: Channel has not been reset properly!\n"? > This is, maybe not so obvious, a warning, which should never fire. It just > proves, that I understand the HW correctly. As long as nobody sees the warning, > it's the case. And it proves that HW behaves according to user manual. > We can remove this warning completely. > > Once again, the story is following: > > - m2p_hw_setup() is always called after channel reset > - after reset channel expects to start from buffer 0 > - therefore we must always start from buffer 0 <= this was not the case before > - we can read the expected "next buffer" from the controller => hence the warning > maybe if there will be a bug somewhere and the channel will not be reset before > next transfer, it will be triggered -- Alexander. -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
