On Thu, Oct 6, 2011 at 6:05 PM, Javier Martinez Canillas
<martinez.jav...@gmail.com> wrote:
> On Thu, Oct 6, 2011 at 5:25 PM, Enrico <ebut...@users.berlios.de> wrote:
>> - i don't see Deepthy patches, it seems to be based on the
>> pre-Deepthy-patches driver and fixed (not that this is a bad thing!);
>> i say this because, like Gary, i'm interested in a possible forward
>> porting to a more recent kernel so i was searching for a starting
>> point
>>
>
> I didn't know there was a more recent version of Deepthy patches,
> Since they are not yet in mainline we should decide if we work on top
> of that or on top of mainline. Deepthy patches are very good to
> separate bt656 and non-bt656 execution inside the ISP, also add a
> platform data variable to decide which mode has to be used.
>
> But reading the documentation and from my experimental validation I
> think that there are a few things that can be improved.
>
> First the assumption that we can use FLDSTAT to check if a frame is
> ODD or EVEN I find to not always be true. Also I don't know who sets
> this value since in the TRM always talks as it is only used with
> discrete syncs.


Yes about FLDSTAT i noticed the same thing. And that's why we need
someone that knows the ISP better to help us....


> Also, I don't think that we should change the ISP CCDC configuration
> inside the VD0 interrupt handler. Since the shadowed registers only
> can be accessed during a frame processing, or more formally the new
> values are taken at the beginning of a frame execution.
>
> By the time we change for example the output address memory for the
> next buffer in the VD0 handler, the next frame is already being
> processed so that value won't be used for the CCDC until that frame
> finish. So It is not behaving as the code expect, since for 3 frames
> the CCDC output memory address will be the same.
>
> That is why I move most of the logic to the VD1 interrupt since there
> the current frame didn't finish yet and we can configure the CCDC for
> the next frame.
>
> But to do that the buffer for the next frame and the releasing of the
> last buffer can't happen simultaneously, that is why I decouple these
> two actions.
>
> Again, this is my own observations and what I understood from the TRM
> and I could be wrong.


I can't comment on that, i hope Laurent or Deepthy will join the discussion...


>> - i don't think that adding the "priv" field in v4l2-mediabus.h will
>> be accepted, and since it is related to the default cropping you added
>> i think it can be dropped and just let the user choose the appropriate
>> cropping
>>
>
> Yes, probably is too much of a hack, but I didn't know of another way
> that the subdev could report to the ISP of the standard and since
> v4l2_pix_format has also a priv field, I think it could be at least a
> temporary solution (remember that we want this to work first and then
> we plan to do it right for upstream submission).


...and my hope continues here.


Enrico
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