Re: Kernel Panic when trying to capture camera with ffmpeg on imx8mp

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Aug 13, 2025 at 01:45:40PM +0200, Maud Spierings wrote:
> On 8/13/25 13:41, Laurent Pinchart wrote:
> > On Wed, Aug 13, 2025 at 02:36:01PM +0300, Laurent Pinchart wrote:
> >> On Wed, Aug 13, 2025 at 01:31:34PM +0200, Maud Spierings wrote:
> >>> On 8/13/25 13:23, Fabio Estevam wrote:
> >>>> Hi Maud,
> >>>>
> >>>> [Adding Tim]
> >>>>
> >>>> On Wed, Aug 13, 2025 at 8:12 AM Maud Spierings wrote:
> >>>>
> >>>>> My devicetree setup is practically identical to the one in
> >>>>> freescale/imx8mp-venice-gw74xx-imx219.dtso (different i2c bus and
> >>>>> regulator gpio only)
> >>>>
> >>>> You'll need to configure the camera pipeline using media-ctl commands.
> >>>>
> >>>> Take a look at:
> >>>> https://trac.gateworks.com/wiki/venice/multimedia#MediaControllerPipeline
> >>>
> >>> I have been messing around with that, but it still shouldn't panic right?
> >>
> >> It shouldn't panic, no. That's a bug in the driver.
> >>
> >>> It seems to be happen in:
> >>> sd = media_entity_to_v4l2_subdev(pad->entity);
> >>>
> >>> in mxc_isi_crossbar_xlate_streams()
> >>>
> >>> Checking now if the pad variable is the issue
> >>>
> >>> it seems media_pad_remote_pad_first() can return NULL which would cause
> >>> the issue there I think.
> > 
> > Can you share the media graph as output by `media-ctl -p -d /dev/media0`
> > just before running ffmpeg ? You may need to replace media0 with the
> > device corresponding to the ISI if you have multiple media devices in
> > the system.
> 
> media-ctl -p -d 1
> Media controller API version 6.12.41
> 
> Media device information
> ------------------------
> driver          mxc-isi
> model           FSL Capture Media Device
> serial
> bus info        platform:32e00000.isi
> hw revision     0x0
> driver version  6.12.41
> 
> Device topology
> - entity 1: crossbar (5 pads, 4 links, 0 routes)
>              type V4L2 subdev subtype Unknown flags 0
>              device node name /dev/v4l-subdev0
>          pad0: SINK,MUST_CONNECT
>                  [stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]
>                  <- "csis-32e40000.csi":1 [ENABLED,IMMUTABLE]
>          pad1: SINK,MUST_CONNECT
>                  [stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]

There's an issue here. The MUST_CONNECT flag should have preventeed the
pipeline from starting when nothing is connected to the pad. I'll test
it locally.

>          pad2: SINK,MUST_CONNECT
>                  <- "mxc_isi.output":0 [ENABLED,IMMUTABLE]
>          pad3: SOURCE
>                  [stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]
>                  -> "mxc_isi.0":0 [ENABLED,IMMUTABLE]
>          pad4: SOURCE
>                  [stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]
>                  -> "mxc_isi.1":0 [ENABLED,IMMUTABLE]
> 
> - entity 7: mxc_isi.0 (2 pads, 2 links, 0 routes)
>              type V4L2 subdev subtype Unknown flags 0
>              device node name /dev/v4l-subdev1
>          pad0: SINK
>                  [stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range
>                   compose.bounds:(0,0)/1920x1080
>                   compose:(0,0)/1920x1080]
>                  <- "crossbar":3 [ENABLED,IMMUTABLE]
>          pad1: SOURCE
>                  [stream:0 fmt:YUV8_1X24/1920x1080 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range
>                   crop.bounds:(0,0)/1920x1080
>                   crop:(0,0)/1920x1080]
>                  -> "mxc_isi.0.capture":0 [ENABLED,IMMUTABLE]
> 
> - entity 10: mxc_isi.0.capture (1 pad, 1 link)
>               type Node subtype V4L flags 0
>               device node name /dev/video1
>          pad0: SINK
>                  <- "mxc_isi.0":1 [ENABLED,IMMUTABLE]
> 
> - entity 18: mxc_isi.1 (2 pads, 2 links, 0 routes)
>               type V4L2 subdev subtype Unknown flags 0
>               device node name /dev/v4l-subdev2
>          pad0: SINK
>                  [stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range
>                   compose.bounds:(0,0)/1920x1080
>                   compose:(0,0)/1920x1080]
>                  <- "crossbar":4 [ENABLED,IMMUTABLE]
>          pad1: SOURCE
>                  [stream:0 fmt:YUV8_1X24/1920x1080 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range
>                   crop.bounds:(0,0)/1920x1080
>                   crop:(0,0)/1920x1080]
>                  -> "mxc_isi.1.capture":0 [ENABLED,IMMUTABLE]
> 
> - entity 21: mxc_isi.1.capture (1 pad, 1 link)
>               type Node subtype V4L flags 0
>               device node name /dev/video2
>          pad0: SINK
>                  <- "mxc_isi.1":1 [ENABLED,IMMUTABLE]
> 
> - entity 29: mxc_isi.output (1 pad, 1 link)
>               type Node subtype V4L flags 0
>          pad0: SOURCE
>                  -> "crossbar":2 [ENABLED,IMMUTABLE]
> 
> - entity 36: csis-32e40000.csi (2 pads, 2 links, 0 routes)
>               type V4L2 subdev subtype Unknown flags 0
>               device node name /dev/v4l-subdev3
>          pad0: SINK,MUST_CONNECT
>                  [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:smpte170m xfer:709 ycbcr:601 quantization:lim-range]
>                  <- "imx219 5-0010":0 []
>          pad1: SOURCE,MUST_CONNECT
>                  [stream:0 fmt:UYVY8_1X16/640x480 field:none colorspace:smpte170m xfer:709 ycbcr:601 quantization:lim-range]
>                  -> "crossbar":0 [ENABLED,IMMUTABLE]
> 
> - entity 41: imx219 5-0010 (1 pad, 1 link, 0 routes)
>               type V4L2 subdev subtype Sensor flags 0
>               device node name /dev/v4l-subdev4
>          pad0: SOURCE
>                  [stream:0 fmt:SRGGB10_1X10/3280x2464 field:none colorspace:raw xfer:none ycbcr:601 quantization:full-range
>                   crop.bounds:(8,8)/3280x2464
>                   crop:(8,8)/3280x2464]
>                  -> "csis-32e40000.csi":0 []
> 
> media0 seems to be dw100, 2 and 3 are hantro-vpu

-- 
Regards,

Laurent Pinchart