drm/i915: use staged outuput config in tv->mode_fixup

The "is this encoder cloned" check will be reused by the lvds encoder,
hence exract it.

v2: Be a bit more careful about that we need to check the new, staged
ouput configuration in the check_non_cloned helper ...

v3: Kill the double negation with s/!non_cloned/is_cloned/, suggested
by Jesse Barnes.
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -6563,6 +6563,28 @@ static struct drm_crtc_helper_funcs intel_helper_funcs = {
 	.disable = intel_crtc_disable,
 };
 
+bool intel_encoder_check_is_cloned(struct intel_encoder *encoder)
+{
+	struct intel_encoder *other_encoder;
+	struct drm_crtc *crtc = &encoder->new_crtc->base;
+
+	if (WARN_ON(!crtc))
+		return false;
+
+	list_for_each_entry(other_encoder,
+			    &crtc->dev->mode_config.encoder_list,
+			    base.head) {
+
+		if (&other_encoder->new_crtc->base != crtc ||
+		    encoder == other_encoder)
+			continue;
+		else
+			return true;
+	}
+
+	return false;
+}
+
 static bool intel_encoder_crtc_ok(struct drm_encoder *encoder,
 				  struct drm_crtc *crtc)
 {

drivers/gpu/drm/i915/intel_drv.h

@@ -454,6 +454,7 @@ extern void intel_crtc_update_dpms(struct drm_crtc *crtc);
 extern void intel_encoder_disable(struct drm_encoder *encoder);
 extern void intel_encoder_destroy(struct drm_encoder *encoder);
 extern void intel_encoder_dpms(struct intel_encoder *encoder, int mode);
+extern bool intel_encoder_check_is_cloned(struct intel_encoder *encoder);
 extern void intel_connector_dpms(struct drm_connector *, int mode);
 extern bool intel_connector_get_hw_state(struct intel_connector *connector);
 extern void intel_connector_check_state(struct intel_connector *);

drivers/gpu/drm/i915/intel_tv.c

@@ -910,16 +910,13 @@ intel_tv_mode_fixup(struct drm_encoder *encoder,
 		    const struct drm_display_mode *mode,
 		    struct drm_display_mode *adjusted_mode)
 {
-	struct drm_device *dev = encoder->dev;
 	struct intel_tv *intel_tv = enc_to_intel_tv(encoder);
 	const struct tv_mode *tv_mode = intel_tv_mode_find(intel_tv);
-	struct intel_encoder *other_encoder;
 
 	if (!tv_mode)
 		return false;
 
-	for_each_encoder_on_crtc(dev, encoder->crtc, other_encoder)
-		if (&other_encoder->base != encoder)
+	if (intel_encoder_check_is_cloned(&intel_tv->base))
 		return false;
 
 	adjusted_mode->clock = tv_mode->clock;