The i9xx modeset sequence is currently pretty fishy, so tight it all
up with some good assert-sprinkling.
We already have good coverage on the disable side, but the enable side
is spotty (since until recently it was wrong).
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
        int reg;
        u32 val;
 
+       assert_pipe_disabled(dev_priv, pipe);
+
        /* No really, not for ILK+ */
        BUG_ON(!IS_VALLEYVIEW(dev_priv->dev) && dev_priv->info->gen >= 5);
 
        int reg;
        u32 val;
 
+       assert_planes_disabled(dev_priv, pipe);
+       assert_sprites_disabled(dev_priv, pipe);
+
        if (HAS_PCH_LPT(dev_priv->dev))
                pch_transcoder = TRANSCODER_A;
        else