drm/amd/display: Check for flip pending before locking pipes

[Why]
When running games or benchmarking with v-sync disabled, disabling
a plane (which is v-sync) can cause underflow. This is caused by
flips pending before pipe locking being applied after locks are
released and pipes could have been re-arranged or disconnected. This
could potentially apply a flip on incorrect pipe. Also, previous logic
of always locking pipes was unnecessary.

[How]
Only lock the pipes when there is a pipe being disabled to increase
efficiency. Before the pipes are locked, check that any pending flips
are cleared to ensure the flips are applied to the correct pipe.
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -2383,7 +2383,6 @@ static void commit_planes_for_stream(struct dc *dc,
 		enum surface_update_type update_type,
 		struct dc_state *context)
 {
-	bool mpcc_disconnected = false;
 	int i, j;
 	struct pipe_ctx *top_pipe_to_program = NULL;
 
@@ -2414,14 +2413,8 @@ static void commit_planes_for_stream(struct dc *dc,
 		context_clock_trace(dc, context);
 	}
 
-	if (update_type != UPDATE_TYPE_FAST && dc->hwss.interdependent_update_lock &&
-		dc->hwss.disconnect_pipes && dc->hwss.wait_for_pending_cleared){
-		dc->hwss.interdependent_update_lock(dc, context, true);
-		mpcc_disconnected = dc->hwss.disconnect_pipes(dc, context);
-		dc->hwss.interdependent_update_lock(dc, context, false);
-		if (mpcc_disconnected)
-			dc->hwss.wait_for_pending_cleared(dc, context);
-	}
+	if (update_type != UPDATE_TYPE_FAST && dc->hwss.interdependent_update_lock && dc->hwss.wait_for_pending_cleared)
+		dc->hwss.disconnect_pipes(dc, context);
 
 	for (j = 0; j < dc->res_pool->pipe_count; j++) {
 		struct pipe_ctx *pipe_ctx = &context->res_ctx.pipe_ctx[j];

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c

@@ -2761,120 +2761,132 @@ static struct pipe_ctx *dcn10_find_top_pipe_for_stream(
 	return NULL;
 }
 
-bool dcn10_disconnect_pipes(
+void dcn10_disconnect_pipes(
 		struct dc *dc,
 		struct dc_state *context)
 {
-		bool found_pipe = false;
-		int i, j;
-		struct dce_hwseq *hws = dc->hwseq;
-		struct dc_state *old_ctx = dc->current_state;
-		bool mpcc_disconnected = false;
-		struct pipe_ctx *old_pipe;
-		struct pipe_ctx *new_pipe;
-		DC_LOGGER_INIT(dc->ctx->logger);
+	bool disconnect_pipes[MAX_PIPES] = {0};
+	bool found_pipe = false;
+	int i, j;
+	struct dce_hwseq *hws = dc->hwseq;
+	struct dc_state *old_ctx = dc->current_state;
+	bool plane_disabled = false;
+	struct pipe_ctx *old_pipe;
+	struct pipe_ctx *new_pipe;
 
-		/* Set pipe update flags and lock pipes */
-		for (i = 0; i < dc->res_pool->pipe_count; i++) {
-			old_pipe = &dc->current_state->res_ctx.pipe_ctx[i];
-			new_pipe = &context->res_ctx.pipe_ctx[i];
-			new_pipe->update_flags.raw = 0;
+	DC_LOGGER_INIT(dc->ctx->logger);
 
-			if (!old_pipe->plane_state && !new_pipe->plane_state)
-				continue;
+	/* Set pipe update flags and lock pipes */
+	for (i = 0; i < dc->res_pool->pipe_count; i++) {
+		old_pipe = &dc->current_state->res_ctx.pipe_ctx[i];
+		new_pipe = &context->res_ctx.pipe_ctx[i];
+		new_pipe->update_flags.raw = 0;
+
+		if (!old_pipe->plane_state && !new_pipe->plane_state)
+			continue;
 
-			if (old_pipe->plane_state && !new_pipe->plane_state)
-				new_pipe->update_flags.bits.disable = 1;
+		if (old_pipe->plane_state && !new_pipe->plane_state)
+			new_pipe->update_flags.bits.disable = 1;
 
-			/* Check for scl update */
-			if (memcmp(&old_pipe->plane_res.scl_data, &new_pipe->plane_res.scl_data, sizeof(struct scaler_data)))
-					new_pipe->update_flags.bits.scaler = 1;
+		/* Check for scl update */
+		if (memcmp(&old_pipe->plane_res.scl_data, &new_pipe->plane_res.scl_data, sizeof(struct scaler_data)))
+			new_pipe->update_flags.bits.scaler = 1;
 
-			/* Check for vp update */
-			if (memcmp(&old_pipe->plane_res.scl_data.viewport, &new_pipe->plane_res.scl_data.viewport, sizeof(struct rect))
-					|| memcmp(&old_pipe->plane_res.scl_data.viewport_c,
+		/* Check for vp update */
+		if (memcmp(&old_pipe->plane_res.scl_data.viewport, &new_pipe->plane_res.scl_data.viewport, sizeof(struct rect))
+				|| memcmp(&old_pipe->plane_res.scl_data.viewport_c,
 						&new_pipe->plane_res.scl_data.viewport_c, sizeof(struct rect)))
-				new_pipe->update_flags.bits.viewport = 1;
+			new_pipe->update_flags.bits.viewport = 1;
 
-		}
+	}
 
-		if (!IS_DIAG_DC(dc->ctx->dce_environment)) {
-			/* Disconnect mpcc here only if losing pipe split*/
-			for (i = 0; i < dc->res_pool->pipe_count; i++) {
-				if (context->res_ctx.pipe_ctx[i].update_flags.bits.disable &&
+	if (!IS_DIAG_DC(dc->ctx->dce_environment)) {
+		/* Disconnect mpcc here only if losing pipe split*/
+		for (i = 0; i < dc->res_pool->pipe_count; i++) {
+			if (context->res_ctx.pipe_ctx[i].update_flags.bits.disable &&
 					old_ctx->res_ctx.pipe_ctx[i].top_pipe) {
 
-					/* Find the top pipe in the new ctx for the bottom pipe that we
-					 * want to remove by comparing the streams and planes. If both
-					 * pipes are being disabled then do it in the regular pipe
-					 * programming sequence
-					 */
-					for (j = 0; j < dc->res_pool->pipe_count; j++) {
-						if (old_ctx->res_ctx.pipe_ctx[i].top_pipe->stream == context->res_ctx.pipe_ctx[j].stream &&
+				/* Find the top pipe in the new ctx for the bottom pipe that we
+				 * want to remove by comparing the streams and planes. If both
+				 * pipes are being disabled then do it in the regular pipe
+				 * programming sequence
+				 */
+				for (j = 0; j < dc->res_pool->pipe_count; j++) {
+					if (old_ctx->res_ctx.pipe_ctx[i].top_pipe->stream == context->res_ctx.pipe_ctx[j].stream &&
 							old_ctx->res_ctx.pipe_ctx[i].top_pipe->plane_state == context->res_ctx.pipe_ctx[j].plane_state &&
 							!context->res_ctx.pipe_ctx[j].top_pipe &&
 							!context->res_ctx.pipe_ctx[j].update_flags.bits.disable) {
-							found_pipe = true;
-							break;
-						}
+						found_pipe = true;
+						break;
 					}
+				}
 
-					// Disconnect if the top pipe lost it's pipe split
-					if (found_pipe && !context->res_ctx.pipe_ctx[j].bottom_pipe) {
-						hws->funcs.plane_atomic_disconnect(dc, &dc->current_state->res_ctx.pipe_ctx[i]);
-						DC_LOG_DC("Reset mpcc for pipe %d\n", dc->current_state->res_ctx.pipe_ctx[i].pipe_idx);
-						mpcc_disconnected = true;
-					}
+				plane_disabled = true;
+
+				// Disconnect if the top pipe lost it's pipe split
+				if (found_pipe && !context->res_ctx.pipe_ctx[j].bottom_pipe) {
+					disconnect_pipes[i] = true;
 				}
-				found_pipe = false;
 			}
+			found_pipe = false;
 		}
+	}
 
-		if (mpcc_disconnected) {
-			for (i = 0; i < dc->res_pool->pipe_count; i++) {
-				struct pipe_ctx *pipe_ctx = &context->res_ctx.pipe_ctx[i];
-				struct pipe_ctx *old_pipe = &dc->current_state->res_ctx.pipe_ctx[i];
-				struct dc_plane_state *plane_state = pipe_ctx->plane_state;
-				struct hubp *hubp = pipe_ctx->plane_res.hubp;
+	if (plane_disabled) {
+		dc->hwss.wait_for_pending_cleared(dc, context);
+		dc->hwss.interdependent_update_lock(dc, context, true);
+
+		for (i = 0; i < dc->res_pool->pipe_count; i++) {
+			struct pipe_ctx *pipe_ctx = &context->res_ctx.pipe_ctx[i];
+			struct pipe_ctx *old_pipe = &dc->current_state->res_ctx.pipe_ctx[i];
+			struct dc_plane_state *plane_state = pipe_ctx->plane_state;
+			struct hubp *hubp = pipe_ctx->plane_res.hubp;
+
+			if (!pipe_ctx || !plane_state || !pipe_ctx->stream)
+				continue;
 
-				if (!pipe_ctx || !plane_state || !pipe_ctx->stream)
-					continue;
+			if (disconnect_pipes[i]) {
+				hws->funcs.plane_atomic_disconnect(dc, &dc->current_state->res_ctx.pipe_ctx[i]);
+				DC_LOG_DC("Reset mpcc for pipe %d\n", dc->current_state->res_ctx.pipe_ctx[i].pipe_idx);
+			}
 
-				// Only update scaler and viewport here if we lose a pipe split.
-				// This is to prevent half the screen from being black when we
-				// unlock after disconnecting MPCC.
-				if (!(old_pipe && !pipe_ctx->top_pipe &&
+			// Only update scaler and viewport here if we lose a pipe split.
+			// This is to prevent half the screen from being black when we
+			// unlock after disconnecting MPCC.
+			if (!(old_pipe && !pipe_ctx->top_pipe &&
 					!pipe_ctx->bottom_pipe && old_pipe->bottom_pipe))
-					continue;
+				continue;
 
-				if (pipe_ctx->update_flags.raw || pipe_ctx->plane_state->update_flags.raw || pipe_ctx->stream->update_flags.raw) {
-					if (pipe_ctx->update_flags.bits.scaler ||
+			if (pipe_ctx->update_flags.raw || pipe_ctx->plane_state->update_flags.raw || pipe_ctx->stream->update_flags.raw) {
+				if (pipe_ctx->update_flags.bits.scaler ||
 						plane_state->update_flags.bits.scaling_change ||
 						plane_state->update_flags.bits.position_change ||
 						plane_state->update_flags.bits.per_pixel_alpha_change ||
 						pipe_ctx->stream->update_flags.bits.scaling) {
 
-						pipe_ctx->plane_res.scl_data.lb_params.alpha_en = pipe_ctx->plane_state->per_pixel_alpha;
-						ASSERT(pipe_ctx->plane_res.scl_data.lb_params.depth == LB_PIXEL_DEPTH_30BPP);
-						/* scaler configuration */
-						pipe_ctx->plane_res.dpp->funcs->dpp_set_scaler(
-						pipe_ctx->plane_res.dpp, &pipe_ctx->plane_res.scl_data);
-					}
+					pipe_ctx->plane_res.scl_data.lb_params.alpha_en = pipe_ctx->plane_state->per_pixel_alpha;
+					ASSERT(pipe_ctx->plane_res.scl_data.lb_params.depth == LB_PIXEL_DEPTH_30BPP);
+					/* scaler configuration */
+					pipe_ctx->plane_res.dpp->funcs->dpp_set_scaler(
+							pipe_ctx->plane_res.dpp, &pipe_ctx->plane_res.scl_data);
+				}
 
-					if (pipe_ctx->update_flags.bits.viewport ||
+				if (pipe_ctx->update_flags.bits.viewport ||
 						(context == dc->current_state && plane_state->update_flags.bits.position_change) ||
 						(context == dc->current_state && plane_state->update_flags.bits.scaling_change) ||
 						(context == dc->current_state && pipe_ctx->stream->update_flags.bits.scaling)) {
 
-						hubp->funcs->mem_program_viewport(
+					hubp->funcs->mem_program_viewport(
 							hubp,
 							&pipe_ctx->plane_res.scl_data.viewport,
 							&pipe_ctx->plane_res.scl_data.viewport_c);
-					}
 				}
 			}
 		}
-	return mpcc_disconnected;
+
+		dc->hwss.interdependent_update_lock(dc, context, false);
+		dc->hwss.wait_for_pending_cleared(dc, context);
+	}
 }
 
 void dcn10_wait_for_pending_cleared(struct dc *dc,

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.h

@@ -194,7 +194,7 @@ void dcn10_get_surface_visual_confirm_color(
 void dcn10_get_hdr_visual_confirm_color(
 		struct pipe_ctx *pipe_ctx,
 		struct tg_color *color);
-bool dcn10_disconnect_pipes(
+void dcn10_disconnect_pipes(
 		struct dc *dc,
 		struct dc_state *context);
 

drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h

@@ -67,7 +67,7 @@ struct hw_sequencer_funcs {
 			int num_planes, struct dc_state *context);
 	void (*program_front_end_for_ctx)(struct dc *dc,
 			struct dc_state *context);
-	bool (*disconnect_pipes)(struct dc *dc,
+	void (*disconnect_pipes)(struct dc *dc,
 			struct dc_state *context);
 	void (*wait_for_pending_cleared)(struct dc *dc,
 			struct dc_state *context);