On Mon, Aug 08, 2016 at 10:45:24AM -0400, Sinan Kaya wrote: > On 8/8/2016 5:02 AM, Vinod Koul wrote: > >> What Vinod is telling me that I need to set the cookie to complete > >> > whether the transaction is successful or not if the request was accepted > >> > by HW. xyz_tx_status is just an indication that the transaction was accepted > >> > by HW. An error can happen as a result of transaction execution. > > Nope, if the txn is completed you mark it complete. If you can detect error > > (can you??) then you can report DMA_ERROR. > > > > Yes, the HW reports if a transaction failed or not. I have this information > available in hidma_ll_status function for a limited amount of time until the > descriptor gets reused. > > > In that latter case do not use dma_async_is_complete() to check. You would > > need to store and report that cookie 'x' failed which you report status in > > .tx_statis() > > > > I really don't like the idea of telling 'hey client I finished your work and I > guarantee you it is complete. A month from now, by the way I actually didn't do > the work that day and I did not tell you' As i said previously, controllers cannot detect errors. In a system DMA burst may go bad due to various different issues which controller has not handle over. So from s system PoV we cannot declare success! > That's why, I preferred not to call the callback when I observe an error which I > think it makes more sense. That doesnt make sense. A client set a callback, it expect you to call one. The result quried maybe txn completed or error. Since you have means, please report.. > Where is the reliability in this? Some random bugs showing at random times. > I'd rather not call the callback and be safe. Especially, if you are talking about > servers; this is plain unacceptable. How does ignoring client wish caller solve this? You are really ona wrong path here. > As Lars-Peter and I indicated in my last email, I think we need to kill this > tx_status API and replace all the clients to use Dave's interface. It is practically > impossible to implement a reliable tx_status function. > > Once this transition happens, I can implement Dave's interface not before. > > Again, it will be a different patch than this one. I think v2 of this patch > needs to go in as it is. > > https://lkml.org/lkml/2016/7/31/64 I havent looked at the patch. If it is not invoking callback set by user, then I am not taking it. Sorry, we dont choose over client's wish. Thanks -- ~Vinod -- 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
