Re: [RFCv1 PATCH 1/6] videobuf2-core: move num_planes from vb2_buffer to vb2_queue.

[Sylwester Nawrocki <s.nawrocki@samsung.com>]

On 09/19/2012 05:28 PM, Hans Verkuil wrote:
> On Wed September 19 2012 17:18:11 Sylwester Nawrocki wrote:
>> Hi Hans,
>>
>> On 09/19/2012 04:37 PM, Hans Verkuil wrote:
>>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>>
>>> It's a queue-global value, so keep it there rather than with the
>>> buffer struct.
>>
>> I would prefer not doing this. It makes the path to variable
>> number of per buffer planes more difficult.
> 
> You can't have a variable number of planes per buffer. You can decide not to
> fill certain planes (e.g. set bytesused to 0 or something), but that's a
> different thing.
> 
> So applications will always need to set up q->num_planes elements of the array.
> And in the MMAP case all planes need to be mmap()ed. You can't have one buffer
> that's setup with only 2 planes while all others are setup with 3 planes.

You're right, all planes would need to be prepared anyway. Reporting that
some planes are unused by setting bytesused is probably going to be enough.
And your subsequent patches depend on this one. FWIW,

Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

--

Regards,
Sylwester