Re: [RFC] ISP lane shifter support

[Michael Jones <michael.jones@matrix-vision.de>]

Hi Laurent,

On 01/24/2011 02:57 PM, Laurent Pinchart wrote:
<snip>
>>>
>>> As the lane shifter is located at the CCDC input, it might be easier to
>>> implement support for this using the CCDC input format. ispvideo.c would
>>> need to validate the pipeline when the output of the entity connected to
>>> the CCDC input (parallel sensor, CCP2 or CSI2) is configured with a
>>> format that can be shifted to the format at the CCDC input.
>>
>> This crossed my mind, but it seems illogical to have a link with a
>> different format at each of its ends.
> 
> I agree in theory, but it might be problematic for the CCDC. Right now the 
> CCDC can write to memory or send the data to the preview engine, but not both 
> at the same time. That's something that I'd like to change in the future. What 
> happens if the user then sets different widths on the output pads ?
> 

Shouldn't we prohibit the user from doing this in ccdc_[try/set]_format
in the first place? By "prohibit", I mean shouldn't we be sure that the
pixel format on pad 1 is always the same as on pad 2?  Downside: this
suggests that set_fmt on pad 2 could change the fmt on pad 1, which may
be unexpected. But that does at least reflect the reality of the
hardware, right?

<snip>

Michael

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