Re: [PATCH v5 38/39] media: imx: csi: fix crop rectangle reset in sink set_fmt

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

On Mon, 2017-03-20 at 14:17 +0000, Russell King - ARM Linux wrote:
> On Mon, Mar 20, 2017 at 03:00:51PM +0100, Philipp Zabel wrote:
> > On Mon, 2017-03-20 at 12:08 +0000, Russell King - ARM Linux wrote:
> > > The same document says:
> > > 
> > >   Scaling support is optional. When supported by a subdev, the crop
> > >   rectangle on the subdev's sink pad is scaled to the size configured
> > >   using the
> > >   :ref:`VIDIOC_SUBDEV_S_SELECTION <VIDIOC_SUBDEV_G_SELECTION>` IOCTL
> > >   using ``V4L2_SEL_TGT_COMPOSE`` selection target on the same pad. If the
> > >   subdev supports scaling but not composing, the top and left values are
> > >   not used and must always be set to zero.
> > 
> > Right, this sentence does imply that when scaling is supported, there
> > must be a sink compose rectangle, even when composing is not.
> > 
> > I have previously set up scaling like this:
> > 
> > media-ctl --set-v4l2 "'ipu1_csi0_mux':2[fmt:UYVY2X8/1920x1080@1/60]"
> > media-ctl --set-v4l2 "'ipu1_csi0':2[fmt:AYUV32/960x540@1/30]"
> > 
> > Does this mean, it should work like this instead?
> > 
> > media-ctl --set-v4l2 "'ipu1_csi0_mux':2[fmt:UYVY2X8/1920x1080@1/60]"
> > media-ctl --set-v4l2 "'ipu1_csi0':0[fmt:UYVY2X8/1920x1080@1/60,compose:(0,0)/960x540]"
> > media-ctl --set-v4l2 "'ipu1_csi0':2[fmt:AYUV32/960x540@1/30]"
> > 
> > I suppose setting the source pad format should not be allowed to modify
> > the sink compose rectangle.
> 
> That is what I believe having read these documents several times, but
> we need v4l2 people to confirm.
> 
> Note that setting the format on 'ipu1_csi0':0 should already be done by
> the previous media-ctl command, so it should be possible to simplify
> that to:
> 
> media-ctl --set-v4l2 "'ipu1_csi0_mux':2[fmt:UYVY2X8/1920x1080@1/60]"
> media-ctl --set-v4l2 "'ipu1_csi0':0[compose:(0,0)/960x540]"
> media-ctl --set-v4l2 "'ipu1_csi0':2[fmt:AYUV32/960x540@1/30]"

Thanks, that works, too.

> I have tripped over a bug in media-ctl when specifying both a crop and
> compose rectangle - the --help output suggests that "," should be used
> to separate them.  media-ctl rejects that, telling me the character at
> the "," should be "]".  Replacing the "," with " " allows media-ctl to
> accept it and set both rectangles, so it sounds like a parser bug - I've
> not looked into this any further yet.

I can confirm this. I don't see any place in
v4l2_subdev_parse_pad_format that handles the "," separator. There's
just whitespace skipping between the v4l2-properties.

regards
Philipp