there is a "camera preview" function in iMX's image processing unit.
User guide explanation is very short:
18.104.22.168.6.3 Camera Preview
• Tearing artifacts can be prevented by (automatic) page-flip double buffering in
• Alternatively, the video stream from an image sensor can be sent directly to the
display buffer used for screen refresh. The significance of this option is that only a
single frame buffer is needed (and not two). This buffer may be located either in
system memory or in an external display controller.
• This option is useful, e.g., in a low frame rate, when tearing is not visible.
• When tearing must be prevented, the refresh cycle in the display can be
synchronized with the timing signals from the sensor (two refresh cycles for each
input frame): the IPU receives a VSYNC signal from the sensor and generates
from it synchronization signals for the display.
The question is: how to configure IPU to stream video directly from sensor to screen without CPU interaction?
Main idea to implement "instant start" appearence, show video from bootloader and then start linux.