VORTEX_SRC_CONVRATIO
hwwrite(vortex->mmio, VORTEX_SRC_CONVRATIO + (src << 2), ratio);
temp = hwread(vortex->mmio, VORTEX_SRC_CONVRATIO + (src << 2));
hw_ratio = hwread(vortex->mmio, VORTEX_SRC_CONVRATIO + (src << 2));
hwwrite(vortex->mmio, VORTEX_SRC_CONVRATIO + (src << 2), desired_ratio);