Revert "drm/i915/skl: New ddb allocation algorithm"

This reverts commit bb9d85f6.

New ddb allocation algorithm is a show stopper on my SKL system.

Besides not be able to get external DP 4k@60 (through USB type C),
It fully hang my screen when unplugging the USB type C.

Bugzilla: https://patchwork.freedesktop.org/patch/161571/
Fixes: bb9d85f6 ("drm/i915/skl: New ddb allocation algorithm")
Cc: Mahesh Kumar <mahesh1.kumar@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1497376350-3400-1-git-send-email-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/intel_pm.c

@@ -4140,41 +4140,13 @@ skl_ddb_calc_min(const struct intel_crtc_state *cstate, int num_active,
 	minimum[PLANE_CURSOR] = skl_cursor_allocation(num_active);
 }
 
-static void
-skl_enable_plane_wm_levels(const struct drm_i915_private *dev_priv,
-			   uint16_t plane_ddb,
-			   uint16_t max_level,
-			   struct skl_plane_wm *wm)
-{
-	int level;
-	/*
-	 * Now enable all levels in WM structure which can be enabled
-	 * using current DDB allocation
-	 */
-	for (level = ilk_wm_max_level(dev_priv); level >= 0; level--) {
-		struct skl_wm_level *level_wm = &wm->wm[level];
-
-		if (level > max_level || level_wm->plane_res_b == 0
-				      || level_wm->plane_res_l >= 31
-				      || level_wm->plane_res_b >= plane_ddb) {
-			level_wm->plane_en = false;
-			level_wm->plane_res_b = 0;
-			level_wm->plane_res_l = 0;
-		} else {
-			level_wm->plane_en = true;
-		}
-	}
-}
-
 static int
 skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
-		      struct skl_pipe_wm *pipe_wm,
 		      struct skl_ddb_allocation *ddb /* out */)
 {
 	struct drm_atomic_state *state = cstate->base.state;
 	struct drm_crtc *crtc = cstate->base.crtc;
 	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	struct skl_ddb_entry *alloc = &cstate->wm.skl.ddb;
@@ -4187,9 +4159,6 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
 	unsigned plane_data_rate[I915_MAX_PLANES] = {};
 	unsigned plane_y_data_rate[I915_MAX_PLANES] = {};
 	uint16_t total_min_blocks = 0;
-	uint16_t total_level_ddb;
-	uint16_t plane_blocks = 0;
-	int max_level, level;
 
 	/* Clear the partitioning for disabled planes. */
 	memset(ddb->plane[pipe], 0, sizeof(ddb->plane[pipe]));
@@ -4228,48 +4197,10 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
 		return -EINVAL;
 	}
 
-	alloc_size -= minimum[PLANE_CURSOR];
-	ddb->plane[pipe][PLANE_CURSOR].start = alloc->end -
-							minimum[PLANE_CURSOR];
+	alloc_size -= total_min_blocks;
+	ddb->plane[pipe][PLANE_CURSOR].start = alloc->end - minimum[PLANE_CURSOR];
 	ddb->plane[pipe][PLANE_CURSOR].end = alloc->end;
 
-	for (level = ilk_wm_max_level(dev_priv); level >= 0; level--) {
-		total_level_ddb = 0;
-		for_each_plane_id_on_crtc(intel_crtc, plane_id) {
-			/*
-			 * TODO: We should calculate watermark values for Y/UV
-			 * plane both in case of NV12 format and use both values
-			 * for ddb calculation. NV12 is disabled as of now, So
-			 * using only single/UV plane value here.
-			 */
-			struct skl_plane_wm *wm = &pipe_wm->planes[plane_id];
-			uint16_t plane_res_b = wm->wm[level].plane_res_b;
-			uint16_t min = minimum[plane_id] + y_minimum[plane_id];
-
-			if (plane_id == PLANE_CURSOR)
-				continue;
-
-			total_level_ddb += max(plane_res_b, min);
-		}
-
-		/*
-		 * If This level can successfully be enabled with the
-		 * pipe's current DDB allocation, then all lower levels are
-		 * guaranteed to succeed as well.
-		 */
-		if (total_level_ddb <= alloc_size)
-			break;
-	}
-
-	if ((level < 0) || (total_min_blocks > alloc_size)) {
-		DRM_DEBUG_KMS("Requested display configuration exceeds system DDB limitations");
-		DRM_DEBUG_KMS("minimum required %d/%d\n", (level < 0) ?
-				total_level_ddb : total_min_blocks, alloc_size);
-		return -EINVAL;
-	}
-	max_level = level;
-	alloc_size -= total_level_ddb;
-
 	/*
 	 * 2. Distribute the remaining space in proportion to the amount of
 	 * data each plane needs to fetch from memory.
@@ -4279,24 +4210,13 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
 	total_data_rate = skl_get_total_relative_data_rate(cstate,
 							   plane_data_rate,
 							   plane_y_data_rate);
-	/*
-	 * PLANE_CURSOR data rate is not included in total_data_rate.
-	 * If only cursor plane is enabled we have to enable its WM levels
-	 * explicitly before returning. Cursor has fixed ddb allocation,
-	 * So it's ok to always check cursor WM enabling before return.
-	 */
-	plane_blocks = skl_ddb_entry_size(&ddb->plane[pipe][PLANE_CURSOR]);
-	skl_enable_plane_wm_levels(dev_priv, plane_blocks, max_level,
-				   &pipe_wm->planes[PLANE_CURSOR]);
 	if (total_data_rate == 0)
 		return 0;
 
 	start = alloc->start;
 	for_each_plane_id_on_crtc(intel_crtc, plane_id) {
 		unsigned int data_rate, y_data_rate;
-		uint16_t plane_blocks = 0, y_plane_blocks = 0;
-		struct skl_plane_wm *wm = &pipe_wm->planes[plane_id];
-		uint16_t plane_res_b = wm->wm[max_level].plane_res_b;
+		uint16_t plane_blocks, y_plane_blocks = 0;
 
 		if (plane_id == PLANE_CURSOR)
 			continue;
@@ -4308,36 +4228,33 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
 		 * promote the expression to 64 bits to avoid overflowing, the
 		 * result is < available as data_rate / total_data_rate < 1
 		 */
+		plane_blocks = minimum[plane_id];
+		plane_blocks += div_u64((uint64_t)alloc_size * data_rate,
+					total_data_rate);
 
 		/* Leave disabled planes at (0,0) */
 		if (data_rate) {
-			plane_blocks = max(minimum[plane_id], plane_res_b);
-			plane_blocks += div_u64((uint64_t)alloc_size *
-					data_rate, total_data_rate);
 			ddb->plane[pipe][plane_id].start = start;
 			ddb->plane[pipe][plane_id].end = start + plane_blocks;
-			start += plane_blocks;
 		}
 
+		start += plane_blocks;
+
 		/*
 		 * allocation for y_plane part of planar format:
-		 * TODO: Once we start calculating watermark values for Y/UV
-		 * plane both consider it for initial allowed wm blocks.
 		 */
 		y_data_rate = plane_y_data_rate[plane_id];
 
-		if (y_data_rate) {
 		y_plane_blocks = y_minimum[plane_id];
-			y_plane_blocks += div_u64((uint64_t)alloc_size *
-					y_data_rate, total_data_rate);
+		y_plane_blocks += div_u64((uint64_t)alloc_size * y_data_rate,
+					total_data_rate);
+
+		if (y_data_rate) {
 			ddb->y_plane[pipe][plane_id].start = start;
 			ddb->y_plane[pipe][plane_id].end = start + y_plane_blocks;
-			start += y_plane_blocks;
 		}
-		skl_enable_plane_wm_levels(dev_priv,
-					   plane_blocks,
-					   max_level,
-					   wm);
+
+		start += y_plane_blocks;
 	}
 
 	return 0;
@@ -4427,9 +4344,11 @@ skl_adjusted_plane_pixel_rate(const struct intel_crtc_state *cstate,
 static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
 				struct intel_crtc_state *cstate,
 				const struct intel_plane_state *intel_pstate,
+				uint16_t ddb_allocation,
 				int level,
 				uint16_t *out_blocks, /* out */
-				uint8_t *out_lines /* out */)
+				uint8_t *out_lines, /* out */
+				bool *enabled /* out */)
 {
 	struct intel_plane *plane = to_intel_plane(intel_pstate->base.plane);
 	const struct drm_plane_state *pstate = &intel_pstate->base;
@@ -4452,8 +4371,10 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
 	bool y_tiled, x_tiled;
 
 	if (latency == 0 ||
-	    !intel_wm_plane_visible(cstate, intel_pstate))
+	    !intel_wm_plane_visible(cstate, intel_pstate)) {
+		*enabled = false;
 		return 0;
+	}
 
 	y_tiled = fb->modifier == I915_FORMAT_MOD_Y_TILED ||
 		  fb->modifier == I915_FORMAT_MOD_Yf_TILED;
@@ -4542,6 +4463,9 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
 		if ((cpp * cstate->base.adjusted_mode.crtc_htotal / 512 < 1) &&
 		    (plane_bytes_per_line / 512 < 1))
 			selected_result = method2;
+		else if ((ddb_allocation && ddb_allocation /
+			fixed_16_16_to_u32_round_up(plane_blocks_per_line)) >= 1)
+			selected_result = min_fixed_16_16(method1, method2);
 		else if (latency >= linetime_us)
 			selected_result = min_fixed_16_16(method1, method2);
 		else
@@ -4561,42 +4485,64 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
 		}
 	}
 
-	if (res_lines >= 31 && level == 0) {
+	if (res_blocks >= ddb_allocation || res_lines > 31) {
+		*enabled = false;
+
+		/*
+		 * If there are no valid level 0 watermarks, then we can't
+		 * support this display configuration.
+		 */
+		if (level) {
+			return 0;
+		} else {
 			struct drm_plane *plane = pstate->plane;
 
 			DRM_DEBUG_KMS("Requested display configuration exceeds system watermark limitations\n");
-		DRM_DEBUG_KMS("[PLANE:%d:%s] lines required = %u/31\n",
-				plane->base.id, plane->name, res_lines);
+			DRM_DEBUG_KMS("[PLANE:%d:%s] blocks required = %u/%u, lines required = %u/31\n",
+				      plane->base.id, plane->name,
+				      res_blocks, ddb_allocation, res_lines);
 			return -EINVAL;
 		}
+	}
 
 	*out_blocks = res_blocks;
 	*out_lines = res_lines;
+	*enabled = true;
 
 	return 0;
 }
 
 static int
 skl_compute_wm_levels(const struct drm_i915_private *dev_priv,
+		      struct skl_ddb_allocation *ddb,
 		      struct intel_crtc_state *cstate,
 		      const struct intel_plane_state *intel_pstate,
 		      struct skl_plane_wm *wm)
 {
+	struct intel_crtc *intel_crtc = to_intel_crtc(cstate->base.crtc);
+	struct drm_plane *plane = intel_pstate->base.plane;
+	struct intel_plane *intel_plane = to_intel_plane(plane);
+	uint16_t ddb_blocks;
+	enum pipe pipe = intel_crtc->pipe;
 	int level, max_level = ilk_wm_max_level(dev_priv);
 	int ret;
 
 	if (WARN_ON(!intel_pstate->base.fb))
 		return -EINVAL;
 
+	ddb_blocks = skl_ddb_entry_size(&ddb->plane[pipe][intel_plane->id]);
+
 	for (level = 0; level <= max_level; level++) {
 		struct skl_wm_level *result = &wm->wm[level];
 
 		ret = skl_compute_plane_wm(dev_priv,
 					   cstate,
 					   intel_pstate,
+					   ddb_blocks,
 					   level,
 					   &result->plane_res_b,
-					   &result->plane_res_l);
+					   &result->plane_res_l,
+					   &result->plane_en);
 		if (ret)
 			return ret;
 	}
@@ -4662,7 +4608,8 @@ static int skl_build_pipe_wm(struct intel_crtc_state *cstate,
 
 		wm = &pipe_wm->planes[plane_id];
 
-		ret = skl_compute_wm_levels(dev_priv, cstate, intel_pstate, wm);
+		ret = skl_compute_wm_levels(dev_priv, ddb, cstate,
+					    intel_pstate, wm);
 		if (ret)
 			return ret;
 		skl_compute_transition_wm(cstate, &wm->trans_wm);
@@ -4775,45 +4722,6 @@ bool skl_ddb_allocation_overlaps(const struct skl_ddb_entry **entries,
 	return false;
 }
 
-static int
-skl_ddb_add_affected_planes(struct intel_crtc_state *cstate,
-			    const struct skl_pipe_wm *old_pipe_wm,
-			    const struct skl_pipe_wm *pipe_wm)
-{
-	struct drm_atomic_state *state = cstate->base.state;
-	struct drm_device *dev = state->dev;
-	struct drm_crtc *crtc = cstate->base.crtc;
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	struct drm_i915_private *dev_priv = to_i915(dev);
-	struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
-	struct skl_ddb_allocation *new_ddb = &intel_state->wm_results.ddb;
-	struct skl_ddb_allocation *cur_ddb = &dev_priv->wm.skl_hw.ddb;
-	struct drm_plane_state *plane_state;
-	struct drm_plane *plane;
-	enum pipe pipe = intel_crtc->pipe;
-
-	WARN_ON(!drm_atomic_get_existing_crtc_state(state, crtc));
-
-	drm_for_each_plane_mask(plane, dev, cstate->base.plane_mask) {
-		enum plane_id plane_id = to_intel_plane(plane)->id;
-		const struct skl_plane_wm *wm = &pipe_wm->planes[plane_id];
-		const struct skl_plane_wm *old_wm = &old_pipe_wm->planes[plane_id];
-
-		if ((skl_ddb_entry_equal(&cur_ddb->plane[pipe][plane_id],
-					&new_ddb->plane[pipe][plane_id]) &&
-		    skl_ddb_entry_equal(&cur_ddb->y_plane[pipe][plane_id],
-					&new_ddb->y_plane[pipe][plane_id])) &&
-		    !memcmp(wm, old_wm, sizeof(struct skl_plane_wm)))
-			continue;
-
-		plane_state = drm_atomic_get_plane_state(state, plane);
-		if (IS_ERR(plane_state))
-			return PTR_ERR(plane_state);
-	}
-
-	return 0;
-}
-
 static int skl_update_pipe_wm(struct drm_crtc_state *cstate,
 			      const struct skl_pipe_wm *old_pipe_wm,
 			      struct skl_pipe_wm *pipe_wm, /* out */
@@ -4827,17 +4735,6 @@ static int skl_update_pipe_wm(struct drm_crtc_state *cstate,
 	if (ret)
 		return ret;
 
-	ret = skl_allocate_pipe_ddb(intel_cstate, pipe_wm, ddb);
-	if (ret)
-		return ret;
-	/*
-	 * TODO: Planes are included in state to arm WM registers.
-	 * Scope to optimize further, by just rewriting plane surf register.
-	 */
-	ret = skl_ddb_add_affected_planes(intel_cstate, old_pipe_wm, pipe_wm);
-	if (ret)
-		return ret;
-
 	if (!memcmp(old_pipe_wm, pipe_wm, sizeof(*pipe_wm)))
 		*changed = false;
 	else
@@ -4860,7 +4757,41 @@ pipes_modified(struct drm_atomic_state *state)
 }
 
 static int
-skl_include_affected_crtcs(struct drm_atomic_state *state)
+skl_ddb_add_affected_planes(struct intel_crtc_state *cstate)
+{
+	struct drm_atomic_state *state = cstate->base.state;
+	struct drm_device *dev = state->dev;
+	struct drm_crtc *crtc = cstate->base.crtc;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
+	struct skl_ddb_allocation *new_ddb = &intel_state->wm_results.ddb;
+	struct skl_ddb_allocation *cur_ddb = &dev_priv->wm.skl_hw.ddb;
+	struct drm_plane_state *plane_state;
+	struct drm_plane *plane;
+	enum pipe pipe = intel_crtc->pipe;
+
+	WARN_ON(!drm_atomic_get_existing_crtc_state(state, crtc));
+
+	drm_for_each_plane_mask(plane, dev, cstate->base.plane_mask) {
+		enum plane_id plane_id = to_intel_plane(plane)->id;
+
+		if (skl_ddb_entry_equal(&cur_ddb->plane[pipe][plane_id],
+					&new_ddb->plane[pipe][plane_id]) &&
+		    skl_ddb_entry_equal(&cur_ddb->y_plane[pipe][plane_id],
+					&new_ddb->y_plane[pipe][plane_id]))
+			continue;
+
+		plane_state = drm_atomic_get_plane_state(state, plane);
+		if (IS_ERR(plane_state))
+			return PTR_ERR(plane_state);
+	}
+
+	return 0;
+}
+
+static int
+skl_compute_ddb(struct drm_atomic_state *state)
 {
 	struct drm_device *dev = state->dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
@@ -4924,6 +4855,14 @@ skl_include_affected_crtcs(struct drm_atomic_state *state)
 		cstate = intel_atomic_get_crtc_state(state, intel_crtc);
 		if (IS_ERR(cstate))
 			return PTR_ERR(cstate);
+
+		ret = skl_allocate_pipe_ddb(cstate, ddb);
+		if (ret)
+			return ret;
+
+		ret = skl_ddb_add_affected_planes(cstate);
+		if (ret)
+			return ret;
 	}
 
 	return 0;
@@ -5013,7 +4952,7 @@ skl_compute_wm(struct drm_atomic_state *state)
 	/* Clear all dirty flags */
 	results->dirty_pipes = 0;
 
-	ret = skl_include_affected_crtcs(state);
+	ret = skl_compute_ddb(state);
 	if (ret)
 		return ret;