Re: [PATCH 1/6 v4] V4L: add two new ioctl()s for multi-size videobuffer management

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On Wed, Aug 17, 2011 at 06:22, Marek Szyprowski
<m.szyprowski@xxxxxxxxxxx> wrote:
> Hello,
>
> On Monday, August 15, 2011 3:46 PM Guennadi Liakhovetski wrote:
>> While switching back, I have to change the struct vb2_ops::queue_setup()
>> operation to take a struct v4l2_create_buffers pointer. An earlier version
>> of this patch just added one more parameter to .queue_setup(), which is
>> easier - changes to videobuf2-core.c are smaller, but it is then
>> redundant. We could use the create pointer for both input and output. The
>> video plane configuration in frame format is the same as what is
>> calculated in .queue_setup(), IIUC. So, we could just let the driver fill
>> that one in. This would require then the videobuf2-core.c to parse struct
>> v4l2_format to decide which union member we need, depending on the buffer
>> type. Do we want this or shall drivers duplicate plane sizes in separate
>> .queue_setup() parameters?
>
> IMHO if possible we should have only one callback for the driver. Please
> notice that the driver should be also allowed to increase (or decrease) the
> number of buffers for particular format/fourcc.
>

Or remove queue_setup altogether (please see my example above). What
do you think Marek?

-- 
Best regards,
Pawel Osciak
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