Re: [PATCH] media: video-mux: fix compliance failures

[Philipp Zabel <p.zabel@pengutronix.de>]

On Wed, 2018-05-23 at 10:53 +0200, Hans Verkuil wrote:
> On 23/05/18 10:47, Philipp Zabel wrote:
> > Hi Hans,
> > 
> > thank you for the review comments.
> > 
> > On Tue, 2018-05-22 at 19:47 +0200, Hans Verkuil wrote:
> > > On 22/05/18 18:29, Philipp Zabel wrote:
> > > > Limit frame sizes to the [1, UINT_MAX-1] interval, media bus formats to
> > > > the available list of formats, and initialize pad and try formats.
> > > > 
> > > > Reported-by: Rui Miguel Silva <rui.silva@linaro.org>
> > > > Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
> > > > ---
> > > >  drivers/media/platform/video-mux.c | 110 +++++++++++++++++++++++++++++
> > > >  1 file changed, 110 insertions(+)
> > > > 
> > > > diff --git a/drivers/media/platform/video-mux.c b/drivers/media/platform/video-mux.c
> > > > index 1fb887293337..ade1dae706aa 100644
> > > > --- a/drivers/media/platform/video-mux.c
> > > > +++ b/drivers/media/platform/video-mux.c
> > > > @@ -180,6 +180,87 @@ static int video_mux_set_format(struct v4l2_subdev *sd,
> > > >  	if (!source_mbusformat)
> > > >  		return -EINVAL;
> > > >  
> > > > +	/* No size limitations except V4L2 compliance requirements */
> > > > +	v4l_bound_align_image(&sdformat->format.width, 1, UINT_MAX - 1, 0,
> > > > +			      &sdformat->format.height, 1, UINT_MAX - 1, 0, 0);
> > > 
> > > This is a bit dubious. I would pick more realistic min/max values like 16 and
> > 
> > Why 16? A grayscale or RGB sensor could crop down to 1x1, see mt9v032
> > for example.
> 
> Was that ever tested? Just because the software allows it, doesn't mean it actually
> works.

I don't know. I'll test this when I get access to a sensor that could
support such low cropping.

I'd just prefer this artificial limit not to be imposed by the generic
video mux driver, as a mux doesn't care about framing.

For example the i.MX media driver currently has an (also artificial)
limit to 16 pixel aligned frame sizes in the CSI subdev anyway.

regards
Philipp