drm/amd/display: Change frontend/backend programming sequence

This is a follow-up to the following change:

Yongqiang Sun: Program front end first when set mode.

Due to pipe-splitting features, how we handle stream enabling and
disabling needs to change.

In the case of pipe split disable, two planes need to be combined back
into the same stream. This needs to be done before any stream
programming happens.

The previous patch addresses this, but breaks cross-platform
compatibility. It's not guaranteed that a dc commit will be called
separately to program planes and streams.

Therefore, we handle the combined commit case by doing plane programming
both before and after stream programming, to handle pipe split disable
and plane enable respectively.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -880,6 +880,33 @@ static enum dc_status dc_commit_state_no_check(struct dc *dc, struct dc_state *c
 	if (!dcb->funcs->is_accelerated_mode(dcb))
 		dc->hwss.enable_accelerated_mode(dc);
 
+	/* Combine planes if required, in case of pipe split disable */
+	for (i = 0; i < dc->current_state->stream_count; i++) {
+		dc->hwss.apply_ctx_for_surface(
+			dc, dc->current_state->streams[i],
+			dc->current_state->stream_status[i].plane_count,
+			dc->current_state);
+	}
+
+	/* Program hardware */
+	dc->hwss.ready_shared_resources(dc, context);
+
+	for (i = 0; i < dc->res_pool->pipe_count; i++) {
+		pipe = &context->res_ctx.pipe_ctx[i];
+		dc->hwss.wait_for_mpcc_disconnect(dc, dc->res_pool, pipe);
+	}
+
+	result = dc->hwss.apply_ctx_to_hw(dc, context);
+
+	if (result != DC_OK)
+		goto fail;
+
+	if (context->stream_count > 1) {
+		enable_timing_multisync(dc, context);
+		program_timing_sync(dc, context);
+	}
+
+	/* Program all planes within new context*/
 	for (i = 0; i < context->stream_count; i++) {
 		const struct dc_sink *sink = context->streams[i]->sink;
 
@@ -911,19 +938,7 @@ static enum dc_status dc_commit_state_no_check(struct dc *dc, struct dc_state *c
 				context->streams[i]->timing.pix_clk_khz);
 	}
 
-	dc->hwss.ready_shared_resources(dc, context);
-
-	for (i = 0; i < dc->res_pool->pipe_count; i++) {
-		pipe = &context->res_ctx.pipe_ctx[i];
-		dc->hwss.wait_for_mpcc_disconnect(dc, dc->res_pool, pipe);
-	}
-	result = dc->hwss.apply_ctx_to_hw(dc, context);
-
-	if (context->stream_count > 1) {
-		enable_timing_multisync(dc, context);
-		program_timing_sync(dc, context);
-	}
-
+fail:
 	dc_enable_stereo(dc, context, dc_streams, context->stream_count);
 
 	dc_release_state(dc->current_state);