RE: [PATCH v3] media: vb2: change queue initialization order

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Hello,

On Monday, August 29, 2011 2:05 PM Guennadi Liakhovetski wrote:

> Hi Marek
> 
> On Mon, 29 Aug 2011, Marek Szyprowski wrote:
> 
> > This patch changes the order of operations during stream on call. Now the
> > buffers are first queued to the driver and then the start_streaming method
> > is called.
> >
> > This resolves the most common case when the driver needs to know buffer
> > addresses to enable dma engine and start streaming. Additional parameter
> > to start_streaming method have been added to simplify drivers code. The
> > driver are now obliged to check if the number of queued buffers is high
> > enough to enable hardware streaming. If not - it can return an error. In
> > such case all the buffers that have been pre-queued are invalidated.
> >
> > This patch also updates all videobuf2 clients to work properly with the
> > changed order of operations.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> > Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> > CC: Pawel Osciak <pawel@xxxxxxxxxx>
> > CC: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> > CC: Hans Verkuil <hverkuil@xxxxxxxxx>
> > CC: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx>
> > CC: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> > CC: Kamil Debski <k.debski@xxxxxxxxxxx>
> > CC: Jonathan Corbet <corbet@xxxxxxx>
> > CC: Josh Wu <josh.wu@xxxxxxxxx>
> > CC: Hans de Goede <hdegoede@xxxxxxxxxx>
> > CC: Paul Mundt <lethal@xxxxxxxxxxxx>
> > ---
> >
> > Hello,
> >
> > This is yet another version of the patch that introduces significant
> > changes in the vb2 streamon operation. I've decided to remove the
> > additional parameter to buf_queue callback and added a few cleanups here
> > and there. This patch also includes an update for all vb2 clients.
> 
> Just for the record: These are not all vb2 clients. A simple grep for
> something like vb2_ops gives you also
> 
> drivers/media/video/mx3_camera.c
> drivers/media/video/sh_mobile_ceu_camera.c

Yes, they are also vb2 clients, but since they don't use start_streaming() 
callback no changes were needed there. Same applies to mem2mem_testdev driver.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center


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