MIPI-CSI Media Pipeline on IMX8M Mini not Working

alexval1323 · ‎07-25-2025

Hi team,

I for the life of me, can not get the /dev/media0 node to show up in user space when trying to configure the media pipeline.I am using the Compulab IMX8M Mini SOM on a custom integration board with a YOCTO build for our use case. I am trying to integrate an Allied Vision camera with their Alvium CSI2 Drivers.

A main baseline question: if the kernel and device tree are set up correctly, the /dev/media0 node will still show up if the pipeline is configured correctly? Or does a driver need to be loaded for the pipeline to initiated successfully? Because regardless, nothing I do can make the media0 node to show up.

At boot time, the camera is not ready to go due to some board setup. Once in user space I (after the power regulators are setup and the camera is ready to go) I rebind the drivers to this output:

root@b2qt-imx8mm-lpddr4-evk:/usr/share/BoardSetup-scripts# ./RebindCamera.sh
Rebinding AVT camera driver...
./RebindCamera.sh: line 7: echo: write error: No such device
[ 43.335322] avt_csi2 0-003c: avt_probe[5107]: /usr/src/debug/avt-csi2/1.2.0+git/avt-csi2.c
[ 43.344799] avt_csi2 0-003c: avt_probe[5147]: no powerdown-gpios defined
[ 43.351676] avt_csi2 0-003c: avt_probe[5164]: devm_gpiod_get_optional(dev, "reset-gpios" succeeded
[ 43.360713] avt_csi2 0-003c: avt_probe[5171]: fwnode_property_present failed to find mipi_csi
[ 43.369373] avt_csi2 0-003c: avt_probe[5188]: bcrm_wait_timeout not found, use default value
[ 43.377842] avt_csi2 0-003c: avt_probe[5191]: bcrm_wait_timeout set to 3000ms
[ 43.385046] avt_csi2 0-003c: avt_csi2_check_mipicfg[4586]: ep_cfg.bus.mipi_csi2.num_data_lanes 1
[ 43.393965] avt_csi2 0-003c: avt_csi2_check_mipicfg[4588]: v4l2_fwnode_ep.nr_of_link_frequencies 2
[ 43.402965] avt_csi2 0-003c: avt_csi2_check_mipicfg[4593]: v4l2_fwnode_ep.link-frequencies 0 value 445500000
[ 43.412824] avt_csi2 0-003c: avt_csi2_check_mipicfg[4593]: v4l2_fwnode_ep.link-frequencies 1 value 891000000
[ 43.422688] avt_csi2 0-003c: avt_probe[5213]: no powerdown-gpios powerdown defined
[ 43.430332] avt_csi2 0-003c: avt_probe[5228]: no reset-gpios defined
[ 43.436726] avt_csi2 0-003c: avt_reset[2080]
[ 43.443043] avt_csi2 0-003c: wait_camera_available[2025]: Waiting for camera to shutdown...
[ 44.648643] avt_csi2 0-003c: wait_camera_available[2033]: Waiting for camera to respond to I2C transfers...
[ 45.269281] kauditd_printk_skb: 15 callbacks suppressed
[ 45.269292] audit: type=1334 audit(1723754849.880:26): prog-id=21 op=UNLOAD
[ 46.664540] avt_csi2 0-003c: wait_camera_available[2054]: Heartbeat supported, waiting for heartbeat to become active
[ 49.878985] avt_csi2 0-003c: wait_camera_available[2064]: Heartbeat active
[ 49.949573] avt_csi2 0-003c: read_cci_registers[748]: regmap_bulk_read(camera->regmap8, cci_cmd_tbl[CCI_REGISTER_LAYOUT_VERSION
].address ret 540
[ 49.969505] avt_csi2 0-003c: cci layout version b: 0x00000100
[ 49.975362] avt_csi2 0-003c: cci layout version a: 0x00010000
[ 49.981170] avt_csi2 0-003c: avt_probe[5285]: read_cci_registers succeeded
[ 49.989267] avt_csi2 0-003c: avt_probe[5302]: bcrm_version_check succeeded
[ 49.996951] avt_csi2 0-003c: bcrm_get_write_handshake_availibility[704]: BCRM write handshake supported!
[ 49.996975] avt_csi2 0-003c: Found camera ALVIUM 1500 C-501c NIR
[ 50.014014] avt_csi2 0-003c: avt_probe[5315]: Firmware version: 0.6.0.8c98 ret = 0
[ 50.024773] avt_csi2 0-003c: correct gcprm version
[ 50.029887] avt_csi2 0-003c: avt_probe[5353]: INIT_WORK(&camera->bcrm_wrhs_work, bcrm_wrhs_work_func);
[ 50.046953] avt_csi2 0-003c: avt_get_sensor_capabilities[4409]: csi clocks
[ 50.046953] camera range: 40000000:750000000 Hz
[ 50.046953] dts nr_of_link_frequencies 2
[ 50.046953] dts link_frequencies[0] 445500000 Hz
[ 50.103673] avt_csi2 0-003c: avt_get_sensor_capabilities[4450]: csi clock read from camera: 443750000 Hz
[ 50.113207] avt_csi2 0-003c: avt_get_sensor_capabilities[4454]: get minimal and maximal resolutions
[ 50.128752] avt_csi2 0-003c: avt_init_avail_formats[1840]: add MEDIA_BUS_FMT_UYVY8_2X8/V4L2_PIX_FMT_UYVY/MIPI_CSI2_DT_YUV422_8B
to list of available formats -1 - 1
[ 50.152546] avt_csi2 0-003c: avt_init_avail_formats[1841]: add MEDIA_BUS_FMT_UYVY8_1X16/V4L2_PIX_FMT_UYVY/MIPI_CSI2_DT_YUV422_8
B to list of available formats -1 - 1
[ 50.167322] avt_csi2 0-003c: avt_init_avail_formats[1842]: add MEDIA_BUS_FMT_YUYV8_1X16/V4L2_PIX_FMT_YUV422P/MIPI_CSI2_DT_YUV42
2_8B to list of available formats -1 - 1
[ 50.182333] avt_csi2 0-003c: avt_init_avail_formats[1843]: add MEDIA_BUS_FMT_YUYV8_2X8/V4L2_PIX_FMT_YUYV/MIPI_CSI2_DT_YUV422_8B
to list of available formats -1 - 1
[ 50.197003] avt_csi2 0-003c: avt_init_avail_formats[1844]: add MEDIA_BUS_FMT_VYUY8_2X8/V4L2_PIX_FMT_VYUY/MIPI_CSI2_DT_YUV422_8B
to list of available formats -1 - 1
[ 50.211670] avt_csi2 0-003c: avt_init_avail_formats[1849]: add MEDIA_BUS_FMT_RGB888_1X24/V4L2_PIX_FMT_RGB24/MIPI_CSI2_DT_RGB888
to list of available formats -1 - 1
[ 50.226343] avt_csi2 0-003c: avt_init_avail_formats[1850]: add MEDIA_BUS_FMT_RBG888_1X24/V4L2_PIX_FMT_RGB24/MIPI_CSI2_DT_RGB888
to list of available formats -1 - 1
[ 50.241008] avt_csi2 0-003c: avt_init_avail_formats[1851]: add MEDIA_BUS_FMT_BGR888_1X24/V4L2_PIX_FMT_RGB24/MIPI_CSI2_DT_RGB888
to list of available formats -1 - 1
[ 50.255682] avt_csi2 0-003c: avt_init_avail_formats[1852]: add MEDIA_BUS_FMT_RGB888_3X8/V4L2_PIX_FMT_RGB24/MIPI_CSI2_DT_RGB888
to list of available formats -1 - 1
[ 50.270271] avt_csi2 0-003c: avt_init_avail_formats[1856]: add MEDIA_BUS_FMT_SGRBG8_1X8/V4L2_PIX_FMT_SGRBG8/MIPI_CSI2_DT_RAW8 t
o list of available formats 1 - 1
[ 50.284685] avt_csi2 0-003c: avt_init_avail_formats[1863]: add MEDIA_BUS_FMT_SGRBG10_1X10/V4L2_PIX_FMT_SGRBG10/MIPI_CSI2_DT_RAW
10 to list of available formats 1 - 1
[ 50.320636] avt_csi2 0-003c: avt_init_controls[3359]: Control Contrast (0x980901) not supported by camera
[ 50.357183] avt_csi2 0-003c: avt_init_controls[3359]: Control Sharpness (0x98091b) not supported by camera
[ 50.367712] avt_csi2 0-003c: avt_update_sw_ctrl_state[2840]: Software trigger control not found!
[ 50.369213] avt_csi2 0-003c: avt_update_sw_ctrl_state[2840]: Software trigger control not found!
[ 50.378025] avt_csi2 0-003c: avt_update_sw_ctrl_state[2840]: Software trigger control not found!
[ 50.412857] mxc_mipi-csi 32e30000.mipi_csi: Registered sensor subdevice: avt_csi2 0-003c
[ 50.429900] avt_csi2 0-003c: camera avt_csi2 0-003c registered
[ 50.435940] avt_csi2 0-003c: -> avt_probe[5420]: sysfs group created! (0)
[ 50.446676] avt_csi2 0-003c: avt_probe[5442]: probe success !
[ 50.378025] avt_csi2 0-003c: avt_update_sw_ctrl_state[2840]: Software trigger control not found!
[ 50.412857] mxc_mipi-csi 32e30000.mipi_csi: Registered sensor subdevice: avt_csi2 0-003c
[ 50.429900] avt_csi2 0-003c: camera avt_csi2 0-003c registered
[ 50.435940] avt_csi2 0-003c: -> avt_probe[5420]: sysfs group created! (0)
[ 50.446676] avt_csi2 0-003c: avt_probe[5442]: probe success !

root@b2qt-imx8mm-lpddr4-evk:/usr/share/BoardSetup-scripts#

At this point I would assume the camera is set up and ready to stream but I cannot get any frames or data in to user space. I use the attached TestStream.sh script:

root@b2qt-imx8mm-lpddr4-evk:/usr/share/BoardSetup-scripts# ./TestStream.sh
./TestStream.sh: line 1: amera: command not found
=== CAMERA STREAMING CONTROL ===
1. Check current camera status:
[ 76.502724] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
Format Video Capture:[ 76.511315] mxc_mipi-csi 32e30000.mipi_csi: format not match

Width/Height : 0/0
[ 76.519017] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
Pixel Format : ''
Field : Any
Bytes per Line : 0
Size Image : 0
Colorspace : Default
Tra[ 76.537857] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
nsfer Function : Default (maps to[ 76.548706] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
Rec. 709)
YCbCr/HSV Encoding: Default (maps to ITU-R 601)
Quantization : Default (maps to Full Range)
Flags :

2. List available co[ 76.570719] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
ntrols:

3. List available form[ 76.581151] mxc_mipi-csi 32e30000.mipi_csi: format not match
ats:
ioctl: VIDIOC_ENUM_FMT
Ty[ 76.589396] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
pe: Video Capture

4. Set a basic format:
[ 76.611180] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.619262] mxc_mipi-csi 32e30000.mipi_csi: format not match
The pixelformat 'UYVY' is invalid[ 76.625042] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1

5. Check if there's a streaming control:
[ 76.647122] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.655283] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1

6. Try to enable streaming (if control exists):
[ 76.672441] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.682040] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
No streaming V4L2 control found
[ 76.699454] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.708214] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
No stream_enable control found

7. Try acquisition start (AVT specific):
[ 76.724226] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.733618] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
No acquisition_start control found

8. Check exposure and gain (make sure they're reasonable):
[ 76.749702] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.759271] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
No exposure control
[ 76.775975] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.784748] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
No gain control

9. Set reasonable exposure/gain if controls exist:
[ 76.801835] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.810768] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
Cannot set exposure
[ 76.827415] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.837494] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
Cannot set gain

10. Try to capture a frame after configuration:
./TestStream.sh: line 47: timeout: command not found
Still no data after streaming configuration

11. Check kernel messages for streaming status:
[ 76.784748] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
[ 76.801835] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.810768] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
[ 76.827415] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 1, camera->power_count 0
[ 76.837494] avt_csi2 0-003c: avt_core_ops_s_power[2156]+: on 0, camera->power_count 1
root@b2qt-imx8mm-lpddr4-evk:/usr/share/BoardSetup-scripts#

Now because the format mismatch, I intend to reset change it through media-ctl on the /dev/media0 node. But that doesn't show up.

Bellow is the core parts of the DTS that are relevant.

// Define your camera on I2C bus
&i2c1 {
/*
* Define the PCAL6416A GPIO expander at I2C address 0x21.
* We give it a label 'gpio_expander' so we can reference it.
*/
gpio_expander: pcal6416a@21 {
compatible = "nxp,pcal6416";
reg = <0x21>;
gpio-controller;
#gpio-cells = <2>;
};

alvium: alvium@3c {
compatible = "alliedvision,avt_csi2";
reg = <0x3c>;
status = "okay";

pinctrl-names = "default";
pinctrl-0 = <&pinctrl_alvium_clk>, <&pinctrl_alvium_gpio>;

// Attollo Specifc Hardware setup for day cam
power-supply = <&dayCam_step2>;
reset-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>;

clocks = <&clk IMX8MM_CLK_CLKO1>;
clock-names = "csi_mclk";
assigned-clocks = <&clk IMX8MM_CLK_CLKO1>;
assigned-clock-parents = <&clk IMX8MM_CLK_24M>;
assigned-clock-rates = <24000000>;

port {
reg = <0>;
alvium_mipi_ep: endpoint {
remote-endpoint = <&mipi1_sensor_ep>;
data-lanes = <2>;
link-frequencies = /bits/ 64 <445500000 891000000>;
mipi-csi;
};
};
};
};

&mipi_csi_1 {
status = "okay";

/delete-node/ port;

port {
mipi1_sensor_ep: endpoint@1 {
reg = <1>;
remote-endpoint = <&alvium_mipi_ep>;
data-lanes = <2>;
csis-hs-settle = <13>;
csis-clk-settle = <2>;
csis-wclk;
};
csi1_mipi_ep: endpoint@2 {
reg = <2>;
remote-endpoint = <&csi1_bridge_in>;
};
};
};

&csi1_bridge {
status = "okay";
fsl,mipi-mode;

/delete-node/ port;

port {
csi1_bridge_in: endpoint {
remote-endpoint = <&csi1_mipi_ep>;
};
};
};

/ {

dayCam_step1: camPowerEnable {
compatible = "regulator-fixed";
regulator-name = "dayCam-Power-Enable";
gpio = <&gpio_expander 5 GPIO_ACTIVE_HIGH>;
enable-active-high;
regulator-always-on;
};

dayCam_step2: dayCamI2cEnable {
compatible = "regulator-fixed";
regulator-name = "dayCam-i2c-Power-Enable";
vin-supply = <&dayCam_step1>;
gpio = <&gpio4 26 GPIO_ACTIVE_HIGH>;
enable-active-high;
regulator-always-on;
// startup-delay-us = <2600000>; // Wait 100ms
};
};

Please help or ideas would be greatly appropriated.