drm/amd/display: fix missing writeback disablement if plane is removed

[Why]
If the plane has been removed, the writeback disablement logic
doesn't run

[How]
fix the logic order
Acked-by: Anson Jacob <Anson.Jacob@amd.com>
Signed-off-by: Roy Chan <roy.chan@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c

@@ -1723,13 +1723,15 @@ void dcn20_program_front_end_for_ctx(
 
 				pipe = pipe->bottom_pipe;
 			}
-			/* Program secondary blending tree and writeback pipes */
-			pipe = &context->res_ctx.pipe_ctx[i];
-			if (!pipe->prev_odm_pipe && pipe->stream->num_wb_info > 0
-					&& (pipe->update_flags.raw || pipe->plane_state->update_flags.raw || pipe->stream->update_flags.raw)
-					&& hws->funcs.program_all_writeback_pipes_in_tree)
-				hws->funcs.program_all_writeback_pipes_in_tree(dc, pipe->stream, context);
 		}
+		/* Program secondary blending tree and writeback pipes */
+		pipe = &context->res_ctx.pipe_ctx[i];
+		if (!pipe->top_pipe && !pipe->prev_odm_pipe
+				&& pipe->stream && pipe->stream->num_wb_info > 0
+				&& (pipe->update_flags.raw || (pipe->plane_state && pipe->plane_state->update_flags.raw)
+					|| pipe->stream->update_flags.raw)
+				&& hws->funcs.program_all_writeback_pipes_in_tree)
+			hws->funcs.program_all_writeback_pipes_in_tree(dc, pipe->stream, context);
 	}
 }
 

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c

@@ -398,12 +398,22 @@ void dcn30_program_all_writeback_pipes_in_tree(
 			for (i_pipe = 0; i_pipe < dc->res_pool->pipe_count; i_pipe++) {
 				struct pipe_ctx *pipe_ctx = &context->res_ctx.pipe_ctx[i_pipe];
 
+				if (!pipe_ctx->plane_state)
+					continue;
+
 				if (pipe_ctx->plane_state == wb_info.writeback_source_plane) {
 					wb_info.mpcc_inst = pipe_ctx->plane_res.mpcc_inst;
 					break;
 				}
 			}
-			ASSERT(wb_info.mpcc_inst != -1);
+
+			if (wb_info.mpcc_inst == -1) {
+				/* Disable writeback pipe and disconnect from MPCC
+				 * if source plane has been removed
+				 */
+				dc->hwss.disable_writeback(dc, wb_info.dwb_pipe_inst);
+				continue;
+			}
 
 			ASSERT(wb_info.dwb_pipe_inst < dc->res_pool->res_cap->num_dwb);
 			dwb = dc->res_pool->dwbc[wb_info.dwb_pipe_inst];