drm/i915: Workaround broken BIOS DBUF configuration on TGL/RKL

From Ville Syrjala
074c88751dc121eb9a7fbcbd632001b8d2b09efa in linux 5.15.y/5.15.29
4e6f55120c7eccf6f9323bb681632e23cbcb3f3c in mainline linux

4 files changed, 74 insertions, 2 deletions

diff --git a/sys/dev/pci/drm/i915/display/intel_display.c b/sys/dev/pci/drm/i915/display/intel_display.c
index 9fd2d414ad2..29e9486ac7e 100644
--- a/sys/dev/pci/drm/i915/display/intel_display.c
+++ b/sys/dev/pci/drm/i915/display/intel_display.c
@@ -1658,8 +1658,8 @@ static void fixup_plane_bitmasks(struct intel_crtc_state *crtc_state)
 	}
 }
 
-static void intel_plane_disable_noatomic(struct intel_crtc *crtc,
-					 struct intel_plane *plane)
+void intel_plane_disable_noatomic(struct intel_crtc *crtc,
+				  struct intel_plane *plane)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	struct intel_crtc_state *crtc_state =
@@ -13234,6 +13234,7 @@ intel_modeset_setup_hw_state(struct drm_device *dev,
 		vlv_wm_sanitize(dev_priv);
 	} else if (DISPLAY_VER(dev_priv) >= 9) {
 		skl_wm_get_hw_state(dev_priv);
+		skl_wm_sanitize(dev_priv);
 	} else if (HAS_PCH_SPLIT(dev_priv)) {
 		ilk_wm_get_hw_state(dev_priv);
 	}
diff --git a/sys/dev/pci/drm/i915/display/intel_display.h b/sys/dev/pci/drm/i915/display/intel_display.h
index e45b344c6ef..98e07dc8c2e 100644
--- a/sys/dev/pci/drm/i915/display/intel_display.h
+++ b/sys/dev/pci/drm/i915/display/intel_display.h
@@ -631,6 +631,8 @@ void intel_plane_unpin_fb(struct intel_plane_state *old_plane_state);
 struct intel_encoder *
 intel_get_crtc_new_encoder(const struct intel_atomic_state *state,
 			   const struct intel_crtc_state *crtc_state);
+void intel_plane_disable_noatomic(struct intel_crtc *crtc,
+				  struct intel_plane *plane);
 
 unsigned int intel_surf_alignment(const struct drm_framebuffer *fb,
 				  int color_plane);
diff --git a/sys/dev/pci/drm/i915/intel_pm.c b/sys/dev/pci/drm/i915/intel_pm.c
index 8752a2a297e..5375683885e 100644
--- a/sys/dev/pci/drm/i915/intel_pm.c
+++ b/sys/dev/pci/drm/i915/intel_pm.c
@@ -6683,6 +6683,74 @@ void skl_wm_get_hw_state(struct drm_i915_private *dev_priv)
 	dbuf_state->enabled_slices = dev_priv->dbuf.enabled_slices;
 }
 
+static bool skl_dbuf_is_misconfigured(struct drm_i915_private *i915)
+{
+	const struct intel_dbuf_state *dbuf_state =
+		to_intel_dbuf_state(i915->dbuf.obj.state);
+	struct skl_ddb_entry entries[I915_MAX_PIPES] = {};
+	struct intel_crtc *crtc;
+
+	for_each_intel_crtc(&i915->drm, crtc) {
+		const struct intel_crtc_state *crtc_state =
+			to_intel_crtc_state(crtc->base.state);
+
+		entries[crtc->pipe] = crtc_state->wm.skl.ddb;
+	}
+
+	for_each_intel_crtc(&i915->drm, crtc) {
+		const struct intel_crtc_state *crtc_state =
+			to_intel_crtc_state(crtc->base.state);
+		u8 slices;
+
+		slices = skl_compute_dbuf_slices(crtc, dbuf_state->active_pipes,
+						 dbuf_state->joined_mbus);
+		if (dbuf_state->slices[crtc->pipe] & ~slices)
+			return true;
+
+		if (skl_ddb_allocation_overlaps(&crtc_state->wm.skl.ddb, entries,
+						I915_MAX_PIPES, crtc->pipe))
+			return true;
+	}
+
+	return false;
+}
+
+void skl_wm_sanitize(struct drm_i915_private *i915)
+{
+	struct intel_crtc *crtc;
+
+	/*
+	 * On TGL/RKL (at least) the BIOS likes to assign the planes
+	 * to the wrong DBUF slices. This will cause an infinite loop
+	 * in skl_commit_modeset_enables() as it can't find a way to
+	 * transition between the old bogus DBUF layout to the new
+	 * proper DBUF layout without DBUF allocation overlaps between
+	 * the planes (which cannot be allowed or else the hardware
+	 * may hang). If we detect a bogus DBUF layout just turn off
+	 * all the planes so that skl_commit_modeset_enables() can
+	 * simply ignore them.
+	 */
+	if (!skl_dbuf_is_misconfigured(i915))
+		return;
+
+	drm_dbg_kms(&i915->drm, "BIOS has misprogrammed the DBUF, disabling all planes\n");
+
+	for_each_intel_crtc(&i915->drm, crtc) {
+		struct intel_plane *plane = to_intel_plane(crtc->base.primary);
+		const struct intel_plane_state *plane_state =
+			to_intel_plane_state(plane->base.state);
+		struct intel_crtc_state *crtc_state =
+			to_intel_crtc_state(crtc->base.state);
+
+		if (plane_state->uapi.visible)
+			intel_plane_disable_noatomic(crtc, plane);
+
+		drm_WARN_ON(&i915->drm, crtc_state->active_planes != 0);
+
+		memset(&crtc_state->wm.skl.ddb, 0, sizeof(crtc_state->wm.skl.ddb));
+	}
+}
+
 static void ilk_pipe_wm_get_hw_state(struct intel_crtc *crtc)
 {
 	struct drm_device *dev = crtc->base.dev;
diff --git a/sys/dev/pci/drm/i915/intel_pm.h b/sys/dev/pci/drm/i915/intel_pm.h
index 91f23b7f0af..79d89fe22d8 100644
--- a/sys/dev/pci/drm/i915/intel_pm.h
+++ b/sys/dev/pci/drm/i915/intel_pm.h
@@ -48,6 +48,7 @@ void skl_pipe_wm_get_hw_state(struct intel_crtc *crtc,
 			      struct skl_pipe_wm *out);
 void g4x_wm_sanitize(struct drm_i915_private *dev_priv);
 void vlv_wm_sanitize(struct drm_i915_private *dev_priv);
+void skl_wm_sanitize(struct drm_i915_private *dev_priv);
 bool intel_can_enable_sagv(struct drm_i915_private *dev_priv,
 			   const struct intel_bw_state *bw_state);
 void intel_sagv_pre_plane_update(struct intel_atomic_state *state);