Hi @thisisausername,
Based on information from the expert team the driver has a default setting length for 512 bytes.
Please have a look to the following driver:
linux-imx/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c at lf-6.6.y · nxp-imx/linux-imx · GitHub
I hope this information will be helpful.
Have a great day!