Re: [PATCHv3 01/12] vb2: add a dev field to use for the default allocation context

[Hans Verkuil <hverkuil@xs4all.nl>]

On 04/23/2016 02:14 AM, Laurent Pinchart wrote:
> Hi Hans,
> 
> Thank you for the patch.
> 
> On Friday 22 Apr 2016 10:38:08 Hans Verkuil wrote:
>> From: Hans Verkuil <hans.verkuil@cisco.com>
>>
>> The allocation context is nothing more than a per-plane device pointer
>> to use when allocating buffers. So just provide a dev pointer in vb2_queue
>> for that purpose and drivers can skip allocating/releasing/filling in
>> the allocation context unless they require different per-plane device
>> pointers as used by some Samsung SoCs.
>>
>> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
>> Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
>> Cc: Sakari Ailus <sakari.ailus@iki.fi>
>> Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
>> Cc: Florian Echtler <floe@butterbrot.org>
>> Cc: Federico Vaga <federico.vaga@gmail.com>
>> Cc: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
>> Cc: Scott Jiang <scott.jiang.linux@gmail.com>
>> Cc: Philipp Zabel <p.zabel@pengutronix.de>
>> Cc: Fabien Dessenne <fabien.dessenne@st.com>
>> Cc: Benoit Parrot <bparrot@ti.com>
>> Cc: Mikhail Ulyanov <mikhail.ulyanov@cogentembedded.com>
>> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
>> Cc: Javier Martin <javier.martin@vista-silicon.com>
>> Cc: Jonathan Corbet <corbet@lwn.net>
>> Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
>> Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
>> Cc: Kyungmin Park <kyungmin.park@samsung.com>
>> Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> ---
>>  drivers/media/v4l2-core/videobuf2-core.c | 16 +++++++++-------
>>  include/media/videobuf2-core.h           |  3 +++
>>  2 files changed, 12 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/media/v4l2-core/videobuf2-core.c
>> b/drivers/media/v4l2-core/videobuf2-core.c index 5d016f4..88b5e48 100644
>> --- a/drivers/media/v4l2-core/videobuf2-core.c
>> +++ b/drivers/media/v4l2-core/videobuf2-core.c
>> @@ -206,8 +206,9 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
>>  	for (plane = 0; plane < vb->num_planes; ++plane) {
>>  		unsigned long size = PAGE_ALIGN(vb->planes[plane].length);
>>
>> -		mem_priv = call_ptr_memop(vb, alloc, q->alloc_ctx[plane],
>> -				      size, dma_dir, q->gfp_flags);
>> +		mem_priv = call_ptr_memop(vb, alloc,
>> +				q->alloc_ctx[plane] ? : &q->dev,
>> +				size, dma_dir, q->gfp_flags);
> 
> While the videobuf2-dma-sg allocation context indeed only contains a pointer 
> to the device, the videobuf2-dma-contig context also contains a dma_attrs. 
> This patch will break the videobuf2-dma-contig alloc implementation.
> 

Good point. I fixed this in the last patch, but that would mean dma-contig would
be broken for the patches in between.

I'm moving dma_attrs to struct vb2_queue as the first patch, then the rest will
work fine.

I've also taken care of the vsp1_video comments.

Regards,

	Hans