drm/i915: account for only one PCH receiver on Haswell

On Haswell, only one pipe can work in FDI mode, so this patch prevents
messing with wrong registers when FDI is being used by non-first pipe. And
to prevent this, we also specify that the VGA can only be used on pipe 0
for now in the crtc_mask value.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 7d59d0e..101c4d4 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -977,9 +977,14 @@
 	u32 val;
 	bool cur_state;
 
-	reg = FDI_RX_CTL(pipe);
-	val = I915_READ(reg);
-	cur_state = !!(val & FDI_RX_ENABLE);
+	if (IS_HASWELL(dev_priv->dev) && pipe > 0) {
+			DRM_ERROR("Attempting to enable FDI_RX on Haswell pipe > 0\n");
+			return;
+	} else {
+		reg = FDI_RX_CTL(pipe);
+		val = I915_READ(reg);
+		cur_state = !!(val & FDI_RX_ENABLE);
+	}
 	WARN(cur_state != state,
 	     "FDI RX state assertion failure (expected %s, current %s)\n",
 	     state_string(state), state_string(cur_state));
@@ -1012,6 +1017,10 @@
 	int reg;
 	u32 val;
 
+	if (IS_HASWELL(dev_priv->dev) && pipe > 0) {
+		DRM_ERROR("Attempting to enable FDI on Haswell with pipe > 0\n");
+		return;
+	}
 	reg = FDI_RX_CTL(pipe);
 	val = I915_READ(reg);
 	WARN(!(val & FDI_RX_PLL_ENABLE), "FDI RX PLL assertion failure, should be active but is disabled\n");
@@ -1483,6 +1492,10 @@
 	assert_fdi_tx_enabled(dev_priv, pipe);
 	assert_fdi_rx_enabled(dev_priv, pipe);
 
+	if (IS_HASWELL(dev_priv->dev) && pipe > 0) {
+		DRM_ERROR("Attempting to enable transcoder on Haswell with pipe > 0\n");
+		return;
+	}
 	reg = TRANSCONF(pipe);
 	val = I915_READ(reg);
 	pipeconf_val = I915_READ(PIPECONF(pipe));