drm/amd/display: Don't overwrite subvp pipe info in fast updates

[Description]
- This is a workaround to avoid concurrency issues -- a fast update
  creates a shallow copy of the dc current_state, and removes all
  subvp/phantom related flags.
- We want to prevent the fast update thread from removing those
  flags in case there's another thread running that requires
  the info for proper programming

Reviewed-by: Jun Lei <[email protected]>
Acked-by: Jasdeep Dhillon <[email protected]>
Signed-off-by: Alvin Lee <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: Alvin Lee

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

@@ -3061,7 +3061,7 @@ static bool update_planes_and_stream_state(struct dc *dc,
 		 * Ensures that we have enough pipes for newly added MPO planes
 		 */
 		if (dc->res_pool->funcs->remove_phantom_pipes)
-			dc->res_pool->funcs->remove_phantom_pipes(dc, context);
+			dc->res_pool->funcs->remove_phantom_pipes(dc, context, false);
 
 		/*remove old surfaces from context */
 		if (!dc_rem_all_planes_for_stream(dc, stream, context)) {

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c

@@ -1743,7 +1743,7 @@ void dcn32_retain_phantom_pipes(struct dc *dc, struct dc_state *context)
 }
 
 // return true if removed piped from ctx, false otherwise
-bool dcn32_remove_phantom_pipes(struct dc *dc, struct dc_state *context)
+bool dcn32_remove_phantom_pipes(struct dc *dc, struct dc_state *context, bool fast_update)
 {
 	int i;
 	bool removed_pipe = false;
@@ -1770,14 +1770,23 @@ bool dcn32_remove_phantom_pipes(struct dc *dc, struct dc_state *context)
 			removed_pipe = true;
 		}
 
-		// Clear all phantom stream info
-		if (pipe->stream) {
-			pipe->stream->mall_stream_config.type = SUBVP_NONE;
-			pipe->stream->mall_stream_config.paired_stream = NULL;
-		}
+		/* For non-full updates, a shallow copy of the current state
+		 * is created. In this case we don't want to erase the current
+		 * state (there can be 2 HIRQL threads, one in flip, and one in
+		 * checkMPO) that can cause a race condition.
+		 *
+		 * This is just a workaround, needs a proper fix.
+		 */
+		if (!fast_update) {
+			// Clear all phantom stream info
+			if (pipe->stream) {
+				pipe->stream->mall_stream_config.type = SUBVP_NONE;
+				pipe->stream->mall_stream_config.paired_stream = NULL;
+			}
 
-		if (pipe->plane_state) {
-			pipe->plane_state->is_phantom = false;
+			if (pipe->plane_state) {
+				pipe->plane_state->is_phantom = false;
+			}
 		}
 	}
 	return removed_pipe;
@@ -1950,23 +1959,28 @@ int dcn32_populate_dml_pipes_from_context(
 		pipes[pipe_cnt].pipe.src.unbounded_req_mode = false;
 		pipes[pipe_cnt].pipe.scale_ratio_depth.lb_depth = dm_lb_19;
 
-		switch (pipe->stream->mall_stream_config.type) {
-		case SUBVP_MAIN:
-			pipes[pipe_cnt].pipe.src.use_mall_for_pstate_change = dm_use_mall_pstate_change_sub_viewport;
-			subvp_in_use = true;
-			break;
-		case SUBVP_PHANTOM:
-			pipes[pipe_cnt].pipe.src.use_mall_for_pstate_change = dm_use_mall_pstate_change_phantom_pipe;
-			pipes[pipe_cnt].pipe.src.use_mall_for_static_screen = dm_use_mall_static_screen_disable;
-			// Disallow unbounded req for SubVP according to DCHUB programming guide
-			pipes[pipe_cnt].pipe.src.unbounded_req_mode = false;
-			break;
-		case SUBVP_NONE:
-			pipes[pipe_cnt].pipe.src.use_mall_for_pstate_change = dm_use_mall_pstate_change_disable;
-			pipes[pipe_cnt].pipe.src.use_mall_for_static_screen = dm_use_mall_static_screen_disable;
-			break;
-		default:
-			break;
+		/* Only populate DML input with subvp info for full updates.
+		 * This is just a workaround -- needs a proper fix.
+		 */
+		if (!fast_validate) {
+			switch (pipe->stream->mall_stream_config.type) {
+			case SUBVP_MAIN:
+				pipes[pipe_cnt].pipe.src.use_mall_for_pstate_change = dm_use_mall_pstate_change_sub_viewport;
+				subvp_in_use = true;
+				break;
+			case SUBVP_PHANTOM:
+				pipes[pipe_cnt].pipe.src.use_mall_for_pstate_change = dm_use_mall_pstate_change_phantom_pipe;
+				pipes[pipe_cnt].pipe.src.use_mall_for_static_screen = dm_use_mall_static_screen_disable;
+				// Disallow unbounded req for SubVP according to DCHUB programming guide
+				pipes[pipe_cnt].pipe.src.unbounded_req_mode = false;
+				break;
+			case SUBVP_NONE:
+				pipes[pipe_cnt].pipe.src.use_mall_for_pstate_change = dm_use_mall_pstate_change_disable;
+				pipes[pipe_cnt].pipe.src.use_mall_for_static_screen = dm_use_mall_static_screen_disable;
+				break;
+			default:
+				break;
+			}
 		}
 
 		pipes[pipe_cnt].dout.dsc_input_bpc = 0;

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.h

@@ -81,7 +81,7 @@ bool dcn32_release_post_bldn_3dlut(
 		struct dc_transfer_func **shaper);
 
 bool dcn32_remove_phantom_pipes(struct dc *dc,
-		struct dc_state *context);
+		struct dc_state *context, bool fast_update);
 
 void dcn32_retain_phantom_pipes(struct dc *dc,
 		struct dc_state *context);

drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c

@@ -1203,7 +1203,7 @@ static void dcn32_full_validate_bw_helper(struct dc *dc,
 		// If SubVP pipe config is unsupported (or cannot be used for UCLK switching)
 		// remove phantom pipes and repopulate dml pipes
 		if (!found_supported_config) {
-			dc->res_pool->funcs->remove_phantom_pipes(dc, context);
+			dc->res_pool->funcs->remove_phantom_pipes(dc, context, false);
 			vba->DRAMClockChangeSupport[*vlevel][vba->maxMpcComb] = dm_dram_clock_change_unsupported;
 			*pipe_cnt = dc->res_pool->funcs->populate_dml_pipes(dc, context, pipes, false);
 
@@ -1518,7 +1518,7 @@ bool dcn32_internal_validate_bw(struct dc *dc,
 		return false;
 
 	// For each full update, remove all existing phantom pipes first
-	dc->res_pool->funcs->remove_phantom_pipes(dc, context);
+	dc->res_pool->funcs->remove_phantom_pipes(dc, context, fast_validate);
 
 	dc->res_pool->funcs->update_soc_for_wm_a(dc, context);
 

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

@@ -240,7 +240,7 @@ struct resource_funcs {
 			unsigned int pipe_cnt,
             unsigned int index);
 
-	bool (*remove_phantom_pipes)(struct dc *dc, struct dc_state *context);
+	bool (*remove_phantom_pipes)(struct dc *dc, struct dc_state *context, bool fast_update);
 	void (*retain_phantom_pipes)(struct dc *dc, struct dc_state *context);
 	void (*get_panel_config_defaults)(struct dc_panel_config *panel_config);
 };