VSYNC
MODE_STATUS(VSYNC),
vsync_reg = VSYNC(pipe);
I915_WRITE(VSYNC(pipe), (490 - 1) | ((492 - 1) << 16));
error->transcoder[i].vsync = I915_READ(VSYNC(cpu_transcoder));
I915_READ(VSYNC(cpu_transcoder)));
I915_WRITE(VSYNC(cpu_transcoder),
tmp = I915_READ(VSYNC(cpu_transcoder));