drm/amd/display: Disable pipe split for modes with borders

[Why]
For some special timing with border, like DMT 640*480 72Hz,
pipe split can't handle well. Thus, it will be black screen
for these special timing.

[How]
Disable pipe split for these timing with borders as W/A.
Signed-off-by: Dale Zhao <dale.zhao@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c

@@ -2666,6 +2666,23 @@ int dcn20_validate_apply_pipe_split_flags(
 	if (plane_count > dc->res_pool->pipe_count / 2)
 		avoid_split = true;
 
+	/* W/A: Mode timing with borders may not work well with pipe split, avoid for this corner case */
+	for (i = 0; i < dc->res_pool->pipe_count; i++) {
+		struct pipe_ctx *pipe = &context->res_ctx.pipe_ctx[i];
+		struct dc_crtc_timing timing;
+
+		if (!pipe->stream)
+			continue;
+		else {
+			timing = pipe->stream->timing;
+			if (timing.h_border_left + timing.h_border_right
+					+ timing.v_border_top + timing.v_border_bottom > 0) {
+				avoid_split = true;
+				break;
+			}
+		}
+	}
+
 	/* Avoid split loop looks for lowest voltage level that allows most unsplit pipes possible */
 	if (avoid_split) {
 		for (i = 0, pipe_idx = 0; i < dc->res_pool->pipe_count; i++) {