Re: i.MX6 MIPI-CSI2 OV5640 Camera testing on Mainline Linux

From: Steve Longerbeam
Date: Tue Oct 23 2018 - 14:12:06 EST



On 10/23/18 10:54 AM, Adam Ford wrote:
On Tue, Oct 23, 2018 at 12:39 PM Steve Longerbeam
<steve_longerbeam@xxxxxxxxxx> wrote:

On 10/23/18 10:34 AM, Adam Ford wrote:
On Tue, Oct 23, 2018 at 11:36 AM Steve Longerbeam
<steve_longerbeam@xxxxxxxxxx> wrote:
Hi Adam,

On 10/23/18 8:19 AM, Adam Ford wrote:
On Mon, Oct 22, 2018 at 7:40 AM Fabio Estevam <festevam@xxxxxxxxx> wrote:
Hi Adam,

On Mon, Oct 22, 2018 at 9:37 AM Adam Ford <aford173@xxxxxxxxx> wrote:

Thank you! This tutorial web site is exactly what I need. The
documentation page in Linux touched on the media-ctl links, but it
didn't explain the syntax or the mapping. This graphical
interpretation really helps it make more sense.
Is capturing working well on your i.MX6 board now?
Fabio,

Unfortunately, no. I built the rootfs based on Jagan's instructions
at https://openedev.amarulasolutions.com/display/ODWIKI/i.CoreM6+1.5

I tried building both the 4.15-RC6 kernel, a 4.19 kernel and a 4.14 LTS kernel.

Using the suggested method of generating the graphical display of the
pipeline options, I am able to enable various pipeline options
connecting different /dev/videoX options tot he camera. I have tried
both the suggested method above as well as the instructions found in
Documentation/media/v4l-drivers/imx.rst for their respective kernels,
and I have tried multiple options to capture through
ipu1_csi1_capture, ipu2_csi1_capture, and ip1_ic_prepenc capture, and
all yield a broken pipe.

libv4l2: error turning on stream: Broken pipe
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Could
not read from resource.
Additional debug info:
gstv4l2bufferpool.c(1064): gst_v4l2_buffer_pool_poll ():
/GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
poll error 1: Broken pipe (32)

I can hear the camera click when I start gstreamer and click again
when it stops trying to stream.

dmesg indicates a broken pipe as well..

[ 2419.851502] ipu2_csi1: pipeline start failed with -32

might you have any suggestions?
This -EPIPE error might mean you have a mis-match of resolution, pixel
format, or field type between one of the source->sink pad links. You can
find out which pads have a mis-match by enabling dynamic debug in the
kernel function __media_pipeline_start.
Following Jagan's suggestion, I tried to make sure all the resolution
and pixel formats were set the same between each source and sink.

media-ctl --set-v4l2 "'ov5640 2-0010':0[fmt:UYVY2X8/640x480
field:none]"
media-ctl --set-v4l2 "'imx6-mipi-csi2':1[fmt:UYVY2X8/640x480
field:none]"
media-ctl --set-v4l2 "'ipu1_csi0_mux':2[fmt:UYVY2X8/640x480
field:none]"
media-ctl --set-v4l2 "'ipu1_csi0':2[fmt:AYUV32/640x480 field:none]"

Also make sure you are attempting to stream from the correct /dev/videoN.
I have graphically plotted the pipeline using media-ctl --print-dot
and I can see the proper video is routed, but your dynamic debug
suggestion yielded something:

imx-media capture-subsystem: link validation failed for 'ov5640
2-0010':0 -> 'imx6-mipi-csi2':0, error -32

It's what I expected, you have a format mismatch between those pads.
Is the mismatch something I am doing wrong with:

media-ctl --set-v4l2 "'ov5640 2-0010':0[fmt:UYVY2X8/640x480 field:none]"
media-ctl --set-v4l2 "'imx6-mipi-csi2':2[fmt:UYVY2X8/640x480 field:none]"

or is there something else I need to do? I just used Jagan's suggestion.


Yeah, that looks correct, media-ctl _should_ automatically propagate the format at 'ov5640 2-0010':0 to 'imx6-mipi-csi2':0. What version of media-ctl are you using? If you have an older version of media-ctl tool that doesn't propagate formats from source->sink pads, you'll have to explicitly set the format at 'imx6-mipi-csi2':0, and at all the other sink pads in your pipeline. Better yet, upgrade! :)

Steve



I am assume this means the interface between the camera and the csi2
isn't working. I am going to double check the power rails and the
clocks. i can hear it click when activated and deactivated, so
something is happening.

adam

Steve