[4/6] dma: tegra: add accurate reporting of dma state

[Dmitry Osipenko <digetx@gmail.com>]

22.02.2019 20:23, Ben Dooks пишет:
> On 21/02/2019 13:02, Dmitry Osipenko wrote:
>> 21.02.2019 13:06, Ben Dooks пишет:
>>> On 21/02/2019 00:41, Dmitry Osipenko wrote:
>>>> 31.10.2018 19:03, Ben Dooks пишет:
>>>>> The tx_status callback does not report the state of the transfer
>>>>> beyond complete segments. This causes problems with users such as
>>>>> ALSA when applications want to know accurately how much data has
>>>>> been moved.
>>>>>
>>>>> This patch addes a function tegra_dma_update_residual() to query
>>>>> the hardware and modify the residual information accordinly. It
>>>>> takes into account any hardware issues when trying to read the
>>>>> state, such as delays between finishing a buffer and signalling
>>>>> the interrupt.
>>>>>
>>>>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>>>>
>>>> Hello Ben,
>>>>
>>>> Do you have any plans to submit a new version of this patch? It's really useful and fixes a real problem with the audio playback. I could help with finalizing the patch and could submit it for you if you happened to lost the interest.
>>>
>>> Personally I think the original version was fine. It has been tested
>>> and returns fairly quickly (I am not a fan of just adding more delay in)
>>>
>>> My notes say the condition doesn't last for long and the loop tends
>>> to terminate within 2 runs.
>>>
>>
>> Okay, so are you going to re-send the patch? We can back to the review after, you need at least to re-send because this series has been outdated. Also please take a look and feel free to use as-is the reduced variant of yours patch that I was carrying and testing for months now [0], it works great.
>>
>> [0] https://github.com/grate-driver/linux/commit/ab8a67a6f47185f265f16749b55df214aaaefad4
>>
> 
> I can try rebasing, but I have not got a lot of time to do any testing
> at the moment. I agree I should have remembered to chase this stuff up
> earlier.

No problems, thank you. I'll help with the testing. And I could rebase the patch and send it out for you if will be needed, please just let me know if you're okay with it.