support for grayscale sensors is missing

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX1
10

Hello JerryChang,

as my sensor is a pure grayscale sensor, I managed to tell that to the kernel to get

s_data->sensor_props->sensor_modes[0].image_properties.pixel_format = V4L2_PIX_FMT_Y12;

This is modeled after what extract_pixel_format does for other sensor formats

after that, my kernel simply crashes :

[    4.138854] Unable to handle kernel NULL pointer dereference at virtual address 00000010
...
[    4.138934] PC is at tegra_channel_update_format+0x14/0xa0
[    4.138944] LR is at tegra_channel_s_ctrl+0x19c/0x230

I then added the following entry to ‘static const struct tegra_video_format vi2_video_formats’ in drivers/media/platform/tegra/camera/vi/vi2_formats.h :

TEGRA_VIDEO_FORMAT(RAW12, 12, Y12_1X12, 2, 1, T_R16_I,
                                RAW12, Y12, "GRAY12"),

With that, I can start linux and list formats :

nvidia@tegra-ubuntu:~$ v4l2-ctl --list-formats
ioctl: VIDIOC_ENUM_FMT
        Index       : 0
        Type        : Video Capture
        Pixel Format: 'Y12 '
        Name        : 12-bit Greyscale

nvidia@tegra-ubuntu:~$

I can also run the command from comment #4, with either RG12 or Y12 as format; that gives me per frame a size of 1920x1080x2 (2 bytes per pixel), but this is clearly not the raw output from my sensor as I can recognize a repeated pattern in the images, which is not in the observed scene.

v4l2src is unusable for Y12; it accepts only GRAY8, GRAY16_BE and GRAY16_LE, so I added other entries to static const struct tegra_video_format vi2_video_formats :

TEGRA_VIDEO_FORMAT(RAW12, 12, Y12_1X12, 1, 1, T_L8,
                                RAW12, GREY, "GRAY8"),
        TEGRA_VIDEO_FORMAT(RAW12, 12, Y12_1X12, 2, 1, T_R16_I,
                                RAW12, Y16, "GRAY16"),

I now have

nvidia@tegra-ubuntu:~$ v4l2-ctl --list-formats
ioctl: VIDIOC_ENUM_FMT
        Index       : 0
        Type        : Video Capture
        Pixel Format: 'GREY'
        Name        : 8-bit Greyscale

        Index       : 1
        Type        : Video Capture
        Pixel Format: 'Y16 '
        Name        : 16-bit Greyscale

nvidia@tegra-ubuntu:~$

That makes v4l2src happy, but the images I get with either v4l2-ctl or a ‘gst-launch-1.0 v4l2src’ pipeline are still garbled.