drm/i915: pixel multiplier readout support for pch ports

Now that we painstakingly track the shared pch dplls we can finally
implement pixel mutliplier readout support for pch ports, too.

v2: Undo the temporary hack to disable the sdvo pixel multiplier
cross-checking.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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 112120e..65e8f5e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5815,10 +5815,6 @@
 
 		ironlake_get_fdi_m_n_config(crtc, pipe_config);
 
-		/* XXX: Can't properly read out the pch dpll pixel multiplier
-		 * since we don't have state tracking for pch clocks yet. */
-		pipe_config->pixel_multiplier = 1;
-
 		if (HAS_PCH_IBX(dev_priv->dev)) {
 			pipe_config->shared_dpll = crtc->pipe;
 		} else {
@@ -5833,6 +5829,11 @@
 
 		WARN_ON(!pll->get_hw_state(dev_priv, pll,
 					   &pipe_config->dpll_hw_state));
+
+		tmp = pipe_config->dpll_hw_state.dpll;
+		pipe_config->pixel_multiplier =
+			((tmp & PLL_REF_SDVO_HDMI_MULTIPLIER_MASK)
+			 >> PLL_REF_SDVO_HDMI_MULTIPLIER_SHIFT) + 1;
 	} else {
 		pipe_config->pixel_multiplier = 1;
 	}
@@ -8083,8 +8084,7 @@
 	PIPE_CONF_CHECK_I(adjusted_mode.crtc_vsync_start);
 	PIPE_CONF_CHECK_I(adjusted_mode.crtc_vsync_end);
 
-	if (!HAS_PCH_SPLIT(dev))
-		PIPE_CONF_CHECK_I(pixel_multiplier);
+	PIPE_CONF_CHECK_I(pixel_multiplier);
 
 	PIPE_CONF_CHECK_FLAGS(adjusted_mode.flags,
 			      DRM_MODE_FLAG_INTERLACE);