FD registers' values

Hi,

For example, when I write a non-zero value to the FD_SIZEX register and then read it out, but the value of FD_SIZEX remain 0, why? (Face detection of DM368)

write to register:

regw_if(config->inputdata.inputImageWidth, FD_SIZEX);

read out from register:

unsigned int valRd = 0x000;

valRd = regr_if(FD_SIZEX);

Anyone can help me? Thanks very much!