Re: [PATCH v9 11/28] rcar-vin: do not allow changing scaling and composing while streaming

Niklas Söderlund
2017-12-20T16:27:01Z

Hi Laurent,

On 2017-12-08 21:20:48 +0200, Laurent Pinchart wrote:
> Hi Niklas,
>
> On Friday, 8 December 2017 16:14:23 EET Niklas Söderlund wrote:
> > On 2017-12-08 11:04:26 +0200, Laurent Pinchart wrote:
> > > On Friday, 8 December 2017 03:08:25 EET Niklas Söderlund wrote:
> > >> It is possible on Gen2 to change the registers controlling composing and
> > >> scaling while the stream is running. It is however not a good idea to do
> > >> so and could result in trouble. There are also no good reasons to allow
> > >> this, remove immediate reflection in hardware registers from
> > >> vidioc_s_selection and only configure scaling and composing when the
> > >> stream starts.
> > >
> > > There is a good reason: digital zoom.
> >
> > OK, so you would recommend me to drop this patch to keep the current
> > behavior?
>
> Yes, unless you don't care about breaking use cases for Gen2, but in that case
> I'd recommend dropping Gen2 support altogether :-)

Well I don't want to do that so I will drop this patch for the next
version. Thanks for clarifying the use-case for this.

>
> > >> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > >> Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
> > >> ---
> > >>
> > >> drivers/media/platform/rcar-vin/rcar-dma.c | 2 +-
> > >> drivers/media/platform/rcar-vin/rcar-v4l2.c | 3 ---
> > >> drivers/media/platform/rcar-vin/rcar-vin.h | 3 ---
> > >> 3 files changed, 1 insertion(+), 7 deletions(-)
>
> [snip]
>
> --
> Regards,
>
> Laurent Pinchart
>

--
Regards,
Niklas Söderlund