DMA_GFX_RB_CNTL__RB_ENABLE_MASK
rb_cntl &= ~DMA_GFX_RB_CNTL__RB_ENABLE_MASK;
WREG32(mmDMA_GFX_RB_CNTL + sdma_offsets[i], rb_cntl | DMA_GFX_RB_CNTL__RB_ENABLE_MASK);