v4l2src launches inconsistently with camera

[Nicolas Dufresne]

Hi,

Le vendredi 15 septembre 2023 à 13:26 -0400, Dwight Kulkarni via gstreamer-devel
a écrit :
> Hi all,
> 
> We have a camera board and are trying to use Gstreamer with it.
> 
> Two different units of the exact same camera board are giving different
> behaviour when launching with gstreamer.
> 
> One of the boards is always launching. Other boards are launching with some
> frequency like 8/10 or 9/10 times. And one of the boards is never launching.

Looks like a driver problem to me.

> 
> When we measure the MIPI output on the camera board, we can measure data there
> when pipeline launches. This means the board is sending data.
> 
> However, for whatever reason Gstreamer some of the time doesn't start up.
> 
> We think it might be some sort of timing issue, but it is very inconsistent. I
> am attaching a sample log which includes dmesg output for the two cases. In
> one case, gstreamer was successful and other case not, in starting up.
> 
> In both instances, we don't see any error message but no stream appears. It
> even says v4l2src was set to PLAYING successfully in both cases.

I've checked the log, its not giving much. Try to set the debug category like
this:

  GST_DEBUG="v4l2*:7,2"

You can also enable v4l2 ioctl traces:

  echo 0xff > /sys/class/video4linux/video1/dev_debug

This will come out on dmesg. These two trace will give you a hint of what the
software is doing. Though, you will not have much hint on what the driver is
doing. As you are on downstream kernel you will have to work with the dowstream
devs to find out more. Upstream linux also have some support through rkisp
driver and libcamera, but no encoder yet.

Nicolas 

> 
> If anyone has any insight into this, would really appreciate it. We have tried
> everything even remaking the board twice, but it seems to be some timing or
> initialization or sequencing issue. 
> 
> -- 
> Sincerely,
> 
> Dwight Kulkarni                
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20230915/b5db365f/attachment.htm>