drm/i915: use cpu/pch transcoder on intel_enable_pipe

This function runs on Haswell, so set the correct pch_transcoder and
cpu_transcoder variables. This fixes an assertion failure on Haswell
VGA.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -1812,9 +1812,15 @@ static void intel_enable_pipe(struct drm_i915_private *dev_priv, enum pipe pipe,
 {
 	enum transcoder cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv,
 								      pipe);
+	enum transcoder pch_transcoder;
 	int reg;
 	u32 val;
 
+	if (IS_HASWELL(dev_priv->dev))
+		pch_transcoder = TRANSCODER_A;
+	else
+		pch_transcoder = pipe;
+
 	/*
 	 * A pipe without a PLL won't actually be able to drive bits from
 	 * a plane.  On ILK+ the pipe PLLs are integrated, so we don't
@@ -1825,8 +1831,8 @@ static void intel_enable_pipe(struct drm_i915_private *dev_priv, enum pipe pipe,
 	else {
 		if (pch_port) {
 			/* if driving the PCH, we need FDI enabled */
-			assert_fdi_rx_pll_enabled(dev_priv, pipe);
-			assert_fdi_tx_pll_enabled(dev_priv, pipe);
+			assert_fdi_rx_pll_enabled(dev_priv, pch_transcoder);
+			assert_fdi_tx_pll_enabled(dev_priv, cpu_transcoder);
 		}
 		/* FIXME: assert CPU port conditions for SNB+ */
 	}