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

Laurent Pinchart
2017-12-08T19:20:50Z

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 :-)

> >> 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