In the earlier parts, FCP_CNTL was at 0x910. But, when the address offsets were redone as of the RV600, this register disappeared. It doesn't seem to be at the equivalent offset in the new register block
The standard pre-RV600 chip mnemonic for the register is FCP_CNTL.
The register should probably be in the CAP0_xxx_xxx registers,
BLOCK_NAME = "VIP";
DESCRIPTION = "VIPH, VIDBLK, VIPDMA, I2C, BIOS, etc. ";
This register was at 0x910 in the pre-RV600 chip
For example, in the rv550.rai file, it looks like this: