drm/amd/display: block odd h_total timings from halving pixel rate

why:
when dynamic odm was turned on, there is also logic to halve the pixelclk
this still turned on when we avoided odm in the case of odd h_total timings

how:
block the pixel clk mechanism also in the case of odd h_total timings
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Martin Leung <Martin.Leung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dio_stream_encoder.c

@@ -243,6 +243,39 @@ static bool is_two_pixels_per_containter(const struct dc_crtc_timing *timing)
 	return two_pix;
 }
 
+static bool is_h_timing_divisible_by_2(const struct dc_crtc_timing *timing)
+{
+	/* math borrowed from function of same name in inc/resource
+	 * checks if h_timing is divisible by 2
+	 */
+
+	bool divisible = false;
+	uint16_t h_blank_start = 0;
+	uint16_t h_blank_end = 0;
+
+	if (timing) {
+		h_blank_start = timing->h_total - timing->h_front_porch;
+		h_blank_end = h_blank_start - timing->h_addressable;
+
+		/* HTOTAL, Hblank start/end, and Hsync start/end all must be
+		 * divisible by 2 in order for the horizontal timing params
+		 * to be considered divisible by 2. Hsync start is always 0.
+		 */
+		divisible = (timing->h_total % 2 == 0) &&
+				(h_blank_start % 2 == 0) &&
+				(h_blank_end % 2 == 0) &&
+				(timing->h_sync_width % 2 == 0);
+	}
+	return divisible;
+}
+
+static bool is_dp_dig_pixel_rate_div_policy(struct dc *dc, const struct dc_crtc_timing *timing)
+{
+	/* should be functionally the same as dcn32_is_dp_dig_pixel_rate_div_policy for DP encoders*/
+	return is_h_timing_divisible_by_2(timing) &&
+		dc->debug.enable_dp_dig_pixel_rate_div_policy;
+}
+
 static void enc32_stream_encoder_dp_unblank(
         struct dc_link *link,
 		struct stream_encoder *enc,
@@ -259,7 +292,7 @@ static void enc32_stream_encoder_dp_unblank(
 
 		/* YCbCr 4:2:0 : Computed VID_M will be 2X the input rate */
 		if (is_two_pixels_per_containter(&param->timing) || param->opp_cnt > 1
-			|| dc->debug.enable_dp_dig_pixel_rate_div_policy) {
+			|| is_dp_dig_pixel_rate_div_policy(dc, &param->timing)) {
 			/*this logic should be the same in get_pixel_clock_parameters() */
 			n_multiply = 1;
 		}

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c

@@ -1161,7 +1161,6 @@ unsigned int dcn32_calculate_dccg_k1_k2_values(struct pipe_ctx *pipe_ctx, unsign
 {
 	struct dc_stream_state *stream = pipe_ctx->stream;
 	unsigned int odm_combine_factor = 0;
-	struct dc *dc = pipe_ctx->stream->ctx->dc;
 	bool two_pix_per_container = false;
 
 	// For phantom pipes, use the same programming as the main pipes
@@ -1189,7 +1188,7 @@ unsigned int dcn32_calculate_dccg_k1_k2_values(struct pipe_ctx *pipe_ctx, unsign
 		} else {
 			*k1_div = PIXEL_RATE_DIV_BY_1;
 			*k2_div = PIXEL_RATE_DIV_BY_4;
-			if ((odm_combine_factor == 2) || dc->debug.enable_dp_dig_pixel_rate_div_policy)
+			if ((odm_combine_factor == 2) || dcn32_is_dp_dig_pixel_rate_div_policy(pipe_ctx))
 				*k2_div = PIXEL_RATE_DIV_BY_2;
 		}
 	}
@@ -1226,7 +1225,6 @@ void dcn32_unblank_stream(struct pipe_ctx *pipe_ctx,
 	struct dc_link *link = stream->link;
 	struct dce_hwseq *hws = link->dc->hwseq;
 	struct pipe_ctx *odm_pipe;
-	struct dc *dc = pipe_ctx->stream->ctx->dc;
 	uint32_t pix_per_cycle = 1;
 
 	params.opp_cnt = 1;
@@ -1245,7 +1243,7 @@ void dcn32_unblank_stream(struct pipe_ctx *pipe_ctx,
 				pipe_ctx->stream_res.tg->inst);
 	} else if (dc_is_dp_signal(pipe_ctx->stream->signal)) {
 		if (optc2_is_two_pixels_per_containter(&stream->timing) || params.opp_cnt > 1
-			|| dc->debug.enable_dp_dig_pixel_rate_div_policy) {
+			|| dcn32_is_dp_dig_pixel_rate_div_policy(pipe_ctx)) {
 			params.timing.pix_clk_100hz /= 2;
 			pix_per_cycle = 2;
 		}
@@ -1262,6 +1260,9 @@ bool dcn32_is_dp_dig_pixel_rate_div_policy(struct pipe_ctx *pipe_ctx)
 {
 	struct dc *dc = pipe_ctx->stream->ctx->dc;
 
+	if (!is_h_timing_divisible_by_2(pipe_ctx->stream))
+		return false;
+
 	if (dc_is_dp_signal(pipe_ctx->stream->signal) && !is_dp_128b_132b_signal(pipe_ctx) &&
 		dc->debug.enable_dp_dig_pixel_rate_div_policy)
 		return true;