Hi Chunghong,
Are you using DM816x EZSDK 5.05.02.00?
See if the below e2e threads will be in help:
http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/211477.aspx
http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/537/t/261353.aspx
http://e2e.ti.com/support/dsp/omap_applications_processors/f/447/t/178686.aspx
http://e2e.ti.com/support/embedded/android/f/509/p/111277/394500.aspx#394500
Regards,
Pavel