how to use tv out in android-2.6.29 kernel


I am using BB rev B7 hardware.
I download kernel 2.6.29 for android from embinux guide to porting android to BB.

my U-boot version is 1.3.3.

I changed the bootargs to “console=ttyS2,115200n8 noinitrd root=/dev/mmcblk0p2 video=omapfb.mode=tv:ntsc init=/init rootfstype=ext3 rw rootdelay=1 nohz=off androidboot.console=ttyS2”

then kernel booted properly, but there is no display in tv.

How to use the new kernel to work with tv out.

Thanks and Regards,