Messages in this thread | | | Subject | Re: [PATCH v5 38/39] media: imx: csi: fix crop rectangle reset in sink set_fmt | From | Steve Longerbeam <> | Date | Mon, 20 Mar 2017 12:48:11 -0700 |
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On 03/20/2017 07:00 AM, Philipp Zabel wrote: > On Mon, 2017-03-20 at 12:08 +0000, Russell King - ARM Linux wrote: >> On Mon, Mar 20, 2017 at 12:55:26PM +0100, Philipp Zabel wrote: >>> The above paragraph suggests we skip any rectangles that are not >>> supported. In our case that would be 3. and 4., since the CSI can't >>> compose into a larger frame. I hadn't realised that the crop selection >>> currently happens on the source pad. >> I'd recommend viewing the documentation in its post-processed version, >> because then you get the examples as pictures, and they say that a >> picture is worth 1000 words. See >> >> https://linuxtv.org/downloads/v4l-dvb-apis/uapi/v4l/dev-subdev.html >> >> There is almost an exact example of what we're trying to do - it's >> figure 4.6. Here, we have a sink pad with a cropping rectangle on >> the input, which is then scaled to a composition rectangle (there's >> no bounds rectangle, and it's specified that in such a case the >> top,left of the composition rectangle will always be 0,0 - see quote >> below). >> >> Where it differs is that the example also supports source cropping >> for two source pads. We don't support that. >> >> 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.
Ok, this all makes consistent sense to me too. So:
- the CSI hardware cropping rectangle should be specified via the sink pad crop selection.
- the CSI hardware /2 downscaler should be specified via the sink pad compose selection.
- the final source pad rectangle is the same as the sink pad compose rectangle.
So that leaves only step 4 (source pad crop selection) as unsupported.
Steve
> 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. > > regards > Philipp >
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