PIPESRC
I915_WRITE(PIPESRC(pipe), ((640 - 1) << 16) | (480 - 1));
error->pipe[i].source = I915_READ(PIPESRC(i));
I915_WRITE(PIPESRC(crtc->pipe),
I915_WRITE(PIPESRC(pipe),
tmp = I915_READ(PIPESRC(crtc->pipe));
val = I915_READ(PIPESRC(pipe));