mmUVD_RB_SIZE2
WREG32_SOC15(UVD, 0, mmUVD_RB_SIZE2, ring->ring_size / 4);
WREG32(mmUVD_RB_SIZE2, ring->ring_size / 4);
WREG32_SOC15(UVD, k, mmUVD_RB_SIZE2, ring->ring_size / 4);
WREG32_SOC15(UVD, 0, mmUVD_RB_SIZE2, ring->ring_size / 4);