diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index fb7fd7de2b76..985defce9908 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1995,6 +1995,13 @@ struct drm_i915_private {
 		 * cstate->wm.need_postvbl_update.
 		 */
 		struct mutex wm_mutex;
+
+		/*
+		 * Set during HW readout of watermarks/DDB.  Some platforms
+		 * need to know when we're still using BIOS-provided values
+		 * (which we don't fully trust).
+		 */
+		bool distrust_bios_wm;
 	} wm;
 
 	struct i915_runtime_pm pm;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5d9909049180..102320c7f3b7 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13594,6 +13594,7 @@ static int intel_atomic_commit(struct drm_device *dev,
 
 	drm_atomic_helper_swap_state(dev, state);
 	dev_priv->wm.config = intel_state->wm_config;
+	dev_priv->wm.distrust_bios_wm = false;
 	intel_shared_dpll_commit(state);
 
 	if (intel_state->modeset) {
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index ca38f6c0e3c8..87fae2e93c40 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4026,6 +4026,14 @@ void skl_wm_get_hw_state(struct drm_device *dev)
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
 		skl_pipe_wm_get_hw_state(crtc);
 
+	if (dev_priv->active_crtcs) {
+		/* Fully recompute DDB on first atomic commit */
+		dev_priv->wm.distrust_bios_wm = true;
+	} else {
+		/* Easy/common case; just sanitize DDB now if everything off */
+		memset(ddb, 0, sizeof(*ddb));
+	}
+
 	/* Calculate plane data rates */
 	for_each_intel_crtc(dev, intel_crtc) {
 		struct intel_crtc_state *cstate = intel_crtc->config;