VLV_GTLC_WAKE_CTRL
s->gtlc_wake_ctrl = I915_READ(VLV_GTLC_WAKE_CTRL);
val = I915_READ(VLV_GTLC_WAKE_CTRL);
I915_WRITE(VLV_GTLC_WAKE_CTRL, val);
val = I915_READ(VLV_GTLC_WAKE_CTRL);
I915_WRITE(VLV_GTLC_WAKE_CTRL, val);
POSTING_READ(VLV_GTLC_WAKE_CTRL);
WARN_ON((I915_READ(VLV_GTLC_WAKE_CTRL) & mask) != mask);