1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 19e94c3edc19..d93dcf683e8c 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2095,6 +2095,43 @@ static void intel_print_wm_latency(struct drm_device *dev,
         }
 }
 
+static bool ilk_increase_wm_latency(struct drm_i915_private *dev_priv,
+                                    uint16_t wm[5], uint16_t min)
+{
+        int level, max_level = ilk_wm_max_level(dev_priv->dev);
+
+        if (wm[0] >= min)
+                return false;
+
+        wm[0] = max(wm[0], min);
+        for (level = 1; level <= max_level; level++)
+                wm[level] = max_t(uint16_t, wm[level], DIV_ROUND_UP(min, 5));
+
+        return true;
+}
+
+static void snb_wm_latency_quirk(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        bool changed;
+
+        /*
+         * The BIOS provided WM memory latency values are often
+         * inadequate for high resolution displays. Adjust them.
+         */
+        changed = ilk_increase_wm_latency(dev_priv, dev_priv->wm.pri_latency, 12) |
+                ilk_increase_wm_latency(dev_priv, dev_priv->wm.spr_latency, 12) |
+                ilk_increase_wm_latency(dev_priv, dev_priv->wm.cur_latency, 12);
+
+        if (!changed)
+                return;
+
+        DRM_DEBUG_KMS("WM latency values increased to avoid potential underruns\n");
+        intel_print_wm_latency(dev, "Primary", dev_priv->wm.pri_latency);
+        intel_print_wm_latency(dev, "Sprite", dev_priv->wm.spr_latency);
+        intel_print_wm_latency(dev, "Cursor", dev_priv->wm.cur_latency);
+}
+
 static void ilk_setup_wm_latency(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
@@ -2112,6 +2149,9 @@ static void ilk_setup_wm_latency(struct drm_device *dev)
         intel_print_wm_latency(dev, "Primary", dev_priv->wm.pri_latency);
         intel_print_wm_latency(dev, "Sprite", dev_priv->wm.spr_latency);
         intel_print_wm_latency(dev, "Cursor", dev_priv->wm.cur_latency);
+
+        if (IS_GEN6(dev))
+                snb_wm_latency_quirk(dev);
 }
 
 static void ilk_compute_wm_parameters(struct drm_crtc *crtc,