mmCG_DISPLAY_GAP_CNTL
tmp = RREG32(mmCG_DISPLAY_GAP_CNTL) & ~(CG_DISPLAY_GAP_CNTL__DISP1_GAP_MASK | CG_DISPLAY_GAP_CNTL__DISP2_GAP_MASK);
WREG32(mmCG_DISPLAY_GAP_CNTL, tmp);
u32 tmp = RREG32(mmCG_DISPLAY_GAP_CNTL);
WREG32(mmCG_DISPLAY_GAP_CNTL, tmp);