drm/i915: Fix SDVO connector and encoder get_hw_state functions

The connector associated with the encoder is considered active when the
output associtated with this connector is active on the encoder. The
encoder itself is considered active when either there is an active
output on  it or the  respective SDVO channel is active.
Having active outputs when the SDVO channel is inactive seems to be
inconsistent: such states can be found when intel_modeset_setup_hw_state()
collects the hardware state set by the BIOS.
This inconsistency will be fixed in intel_sanitize_crtc()
(when intel_crtc_update_dpms() is called), this however only happens
when the encoder is associated with a crtc.

This patch also reverts:

     commit bd6946e8
     Author: Daniel Vetter <daniel.vetter@ffwll.ch>
     Date:   Tue Apr 2 21:30:34 2013 +0200

         drm/i915: Fix sdvo connector get_hw_state function
Signed-off-by: Egbert Eich <eich@suse.de>
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=63031
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1231,12 +1231,8 @@ static bool intel_sdvo_connector_get_hw_state(struct intel_connector *connector)
 	struct intel_sdvo_connector *intel_sdvo_connector =
 		to_intel_sdvo_connector(&connector->base);
 	struct intel_sdvo *intel_sdvo = intel_attached_sdvo(&connector->base);
-	struct drm_i915_private *dev_priv = intel_sdvo->base.base.dev->dev_private;
 	u16 active_outputs;
 
-	if (!(I915_READ(intel_sdvo->sdvo_reg) & SDVO_ENABLE))
-		return false;
-
 	intel_sdvo_get_active_outputs(intel_sdvo, &active_outputs);
 
 	if (active_outputs & intel_sdvo_connector->output_flag)
@@ -1251,11 +1247,13 @@ static bool intel_sdvo_get_hw_state(struct intel_encoder *encoder,
 	struct drm_device *dev = encoder->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_sdvo *intel_sdvo = to_intel_sdvo(&encoder->base);
+	u16 active_outputs;
 	u32 tmp;
 
 	tmp = I915_READ(intel_sdvo->sdvo_reg);
+	intel_sdvo_get_active_outputs(intel_sdvo, &active_outputs);
 
-	if (!(tmp & SDVO_ENABLE))
+	if (!(tmp & SDVO_ENABLE) && (active_outputs == 0))
 		return false;
 
 	if (HAS_PCH_CPT(dev))
@@ -2746,7 +2744,6 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
 	struct intel_sdvo *intel_sdvo;
 	u32 hotplug_mask;
 	int i;
-
 	intel_sdvo = kzalloc(sizeof(struct intel_sdvo), GFP_KERNEL);
 	if (!intel_sdvo)
 		return false;