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

[Dmitry Osipenko <digetx@gmail.com>]

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 We can back to the review after, you need at least to re-send because this series has been outdated.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