Anatolij,
Since commit d37618d18d49 ("imx: convert gwventana board to DM_VIDEO") video support for IMX6 based Ventana boards has been broken.
I find that while the bind function for fsl_imx6q_ipu is called the probe never is (ipuv3_video_probe). Do you know why this is?
I see that with commit 57f065fee2a4 ("video: ipuv3: add DM_VIDEO support") you mention that DTS files must include 'u-boot,dm-pre-reloc' for soc/ipu nodes to enable driver binding to ipu device but I haven't been able to get that to make a difference nor have I found a board that does this. You did add those props to imx6qdl.dtsi at one point but they are no longer there.
There must have been several other IMX6 boards with video support that were affected by this so perhaps I'm missing something simple.
Best regards,
Tim