[PATCH] drm/i915: fixup the plane->pipe fixup code

[Daniel Vetter <daniel.vetter@ffwll.ch>]

We need to check whether the _other plane is on our pipe, not whether
our plane is on the other pipe. Otherwise if not both pipes/planes are
active, we won't properly clean up the mess and set up our desired
plane->pipe mapping.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=51265
Tested-by: Vladyslav Shtabovenko <DFEW.Entwickler@googlemail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/intel_display.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index fd9c275..ce9b247 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7994,11 +7994,27 @@ static void intel_enable_pipe_a(struct drm_device *dev)
 
 }
 
+static bool
+intel_check_plane_mapping(struct intel_crtc *crtc)
+{
+	struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
+	u32 reg, val;
+
+	reg = DSPCNTR(!crtc->plane);
+	val = I915_READ(reg);
+
+	if ((val & DISPLAY_PLANE_ENABLE) == 0 &&
+	    (!!(val & DISPPLANE_SEL_PIPE_MASK) == crtc->pipe))
+		return false;
+
+	return true;
+}
+
 static void intel_sanitize_crtc(struct intel_crtc *crtc)
 {
 	struct drm_device *dev = crtc->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 reg, val;
+	u32 reg;
 
 	/* Clear any frame start delays used for debugging left by the BIOS */
 	reg = PIPECONF(crtc->pipe);
@@ -8006,17 +8022,10 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc)
 
 	/* We need to sanitize the plane -> pipe mapping first because this will
 	 * disable the crtc (and hence change the state) if it is wrong. */
-	if (!HAS_PCH_SPLIT(dev)) {
+	if (!HAS_PCH_SPLIT(dev) && !intel_check_plane_mapping(crtc)) {
 		struct intel_connector *connector;
 		bool plane;
 
-		reg = DSPCNTR(crtc->plane);
-		val = I915_READ(reg);
-
-		if ((val & DISPLAY_PLANE_ENABLE) == 0 &&
-		    (!!(val & DISPPLANE_SEL_PIPE_MASK) == crtc->pipe))
-			goto ok;
-
 		DRM_DEBUG_KMS("[CRTC:%d] wrong plane connection detected!\n",
 			      crtc->base.base.id);
 
@@ -8040,7 +8049,6 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc)
 		WARN_ON(crtc->active);
 		crtc->base.enabled = false;
 	}
-ok:
 
 	if (dev_priv->quirks & QUIRK_PIPEA_FORCE &&
 	    crtc->pipe == PIPE_A && !crtc->active) {
-- 
1.7.11.2