3 files changed, 32 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index ed5d4f4d702e..ad3a0187d306 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2971,6 +2971,24 @@ static void ironlake_pch_enable(struct drm_crtc *crtc)
         intel_enable_transcoder(dev_priv, pipe);
 }
 
+void intel_cpt_verify_modeset(struct drm_device *dev, int pipe)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        int dslreg = PIPEDSL(pipe), tc2reg = TRANS_CHICKEN2(pipe);
+        u32 temp;
+
+        temp = I915_READ(dslreg);
+        udelay(500);
+        if (wait_for(I915_READ(dslreg) != temp, 5)) {
+                /* Without this, mode sets may fail silently on FDI */
+                I915_WRITE(tc2reg, TRANS_AUTOTRAIN_GEN_STALL_DIS);
+                udelay(250);
+                I915_WRITE(tc2reg, 0);
+                if (wait_for(I915_READ(dslreg) != temp, 5))
+                        DRM_ERROR("mode set failed: pipe %d stuck\n", pipe);
+        }
+}
+
 static void ironlake_crtc_enable(struct drm_crtc *crtc)
 {
         struct drm_device *dev = crtc->dev;
@@ -3340,8 +3358,15 @@ void intel_encoder_prepare(struct drm_encoder *encoder)
 void intel_encoder_commit(struct drm_encoder *encoder)
 {
         struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
+        struct drm_device *dev = encoder->dev;
+        struct intel_encoder *intel_encoder = to_intel_encoder(encoder);
+        struct intel_crtc *intel_crtc = to_intel_crtc(intel_encoder->base.crtc);
+
         /* lvds has its own version of commit see intel_lvds_commit */
         encoder_funcs->dpms(encoder, DRM_MODE_DPMS_ON);
+
+        if (HAS_PCH_CPT(dev))
+                intel_cpt_verify_modeset(dev, intel_crtc->pipe);
 }
 
 void intel_encoder_destroy(struct drm_encoder *encoder)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3009d2aaaa3a..74c835272292 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1191,6 +1191,8 @@ static void intel_dp_prepare(struct drm_encoder *encoder)
 static void intel_dp_commit(struct drm_encoder *encoder)
 {
         struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+        struct drm_device *dev = encoder->dev;
+        struct intel_crtc *intel_crtc = to_intel_crtc(intel_dp->base.base.crtc);
 
         ironlake_edp_panel_vdd_on(intel_dp);
         intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
@@ -1202,6 +1204,9 @@ static void intel_dp_commit(struct drm_encoder *encoder)
         ironlake_edp_backlight_on(intel_dp);
 
         intel_dp->dpms_mode = DRM_MODE_DPMS_ON;
+
+        if (HAS_PCH_CPT(dev))
+                intel_cpt_verify_modeset(dev, intel_crtc->pipe);
 }
 
 static void
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 5829854ecbf6..51b1d752940b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -382,4 +382,6 @@ extern void intel_fb_restore_mode(struct drm_device *dev);
 extern void intel_init_clock_gating(struct drm_device *dev);
 extern void intel_write_eld(struct drm_encoder *encoder,
                             struct drm_display_mode *mode);
+extern void intel_cpt_verify_modeset(struct drm_device *dev, int pipe);
+
 #endif /* __INTEL_DRV_H__ */