1 files changed, 44 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3da9c0f9e948..248128126422 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15415,16 +15415,45 @@ static void intel_sanitize_crtc(struct intel_crtc *crtc,
 	}
 }
 
+static bool has_bogus_dpll_config(const struct intel_crtc_state *crtc_state)
+{
+	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
+
+	/*
+	 * Some SNB BIOSen (eg. ASUS K53SV) are known to misprogram
+	 * the hardware when a high res displays plugged in. DPLL P
+	 * divider is zero, and the pipe timings are bonkers. We'll
+	 * try to disable everything in that case.
+	 *
+	 * FIXME would be nice to be able to sanitize this state
+	 * without several WARNs, but for now let's take the easy
+	 * road.
+	 */
+	return IS_GEN6(dev_priv) &&
+		crtc_state->base.active &&
+		crtc_state->shared_dpll &&
+		crtc_state->port_clock == 0;
+}
+
 static void intel_sanitize_encoder(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_connector *connector;
+	struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc);
+	struct intel_crtc_state *crtc_state = crtc ?
+		to_intel_crtc_state(crtc->base.state) : NULL;
 
 	/* We need to check both for a crtc link (meaning that the
 	 * encoder is active and trying to read from a pipe) and the
 	 * pipe itself being active. */
-	bool has_active_crtc = encoder->base.crtc &&
-		to_intel_crtc(encoder->base.crtc)->active;
+	bool has_active_crtc = crtc_state &&
+		crtc_state->base.active;
+
+	if (crtc_state && has_bogus_dpll_config(crtc_state)) {
+		DRM_DEBUG_KMS("BIOS has misprogrammed the hardware. Disabling pipe %c\n",
+			      pipe_name(crtc->pipe));
+		has_active_crtc = false;
+	}
 
 	connector = intel_encoder_find_connector(encoder);
 	if (connector && !has_active_crtc) {
@@ -15435,16 +15464,25 @@ static void intel_sanitize_encoder(struct intel_encoder *encoder)
 		/* Connector is active, but has no active pipe. This is
 		 * fallout from our resume register restoring. Disable
 		 * the encoder manually again. */
-		if (encoder->base.crtc) {
-			struct drm_crtc_state *crtc_state = encoder->base.crtc->state;
+		if (crtc_state) {
+			struct drm_encoder *best_encoder;
 
 			DRM_DEBUG_KMS("[ENCODER:%d:%s] manually disabled\n",
 				      encoder->base.base.id,
 				      encoder->base.name);
+
+			/* avoid oopsing in case the hooks consult best_encoder */
+			best_encoder = connector->base.state->best_encoder;
+			connector->base.state->best_encoder = &encoder->base;
+
 			if (encoder->disable)
-				encoder->disable(encoder, to_intel_crtc_state(crtc_state), connector->base.state);
+				encoder->disable(encoder, crtc_state,
+						 connector->base.state);
 			if (encoder->post_disable)
-				encoder->post_disable(encoder, to_intel_crtc_state(crtc_state), connector->base.state);
+				encoder->post_disable(encoder, crtc_state,
+						      connector->base.state);
+
+			connector->base.state->best_encoder = best_encoder;
 		}
 		encoder->base.crtc = NULL;