drm_i915_get_pipe_from_crtc_id
struct drm_i915_get_pipe_from_crtc_id *pipe_from_crtc_id = data;
#define DRM_IOCTL_I915_GET_PIPE_FROM_CRTC_ID DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GET_PIPE_FROM_CRTC_ID, struct drm_i915_get_pipe_from_crtc_id)