Good to hear that color bar test is working fine. Now it is just displaylink that we should make it working.
Did you check that when set_fmt ioclt is called, the frame size that is used is 720x576 and it is not getting reconfigured to any other resolution?
Also can you tell me which display path that you are using? I want to check the frame size set in the internal modules and make sure it is correct?
Regards,
Brijesh