drm/amd/display: Fix setting DP_VID_N_MUL

[Why]
Need to set VID_N_MUL for 4:2:0 cases

[How]
Move setting to enc1_stream_encoder_dp_unblank and
ensure it is also set for non-4:2:0 cases.
Signed-off-by: Eric Bernstein <eric.bernstein@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c

@@ -1054,6 +1054,7 @@ void dce110_unblank_stream(struct pipe_ctx *pipe_ctx,
 	/* only 3 items below are used by unblank */
 	params.pixel_clk_khz = pipe_ctx->stream->timing.pix_clk_100hz / 10;
 	params.link_settings.link_rate = link_settings->link_rate;
+	params.pixel_encoding = pipe_ctx->stream->timing.pixel_encoding;
 
 	if (dc_is_dp_signal(pipe_ctx->stream->signal))
 		pipe_ctx->stream_res.stream_enc->funcs->dp_unblank(pipe_ctx->stream_res.stream_enc, &params);

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c

@@ -298,7 +298,6 @@ void enc1_stream_encoder_dp_set_stream_attribute(
 		break;
 	case PIXEL_ENCODING_YCBCR420:
 		dp_pixel_encoding = DP_PIXEL_ENCODING_TYPE_YCBCR420;
-		REG_UPDATE(DP_VID_TIMING, DP_VID_N_MUL, 1);
 		break;
 	default:
 		dp_pixel_encoding = DP_PIXEL_ENCODING_TYPE_RGB444;
@@ -833,13 +832,17 @@ void enc1_stream_encoder_dp_unblank(
 	if (param->link_settings.link_rate != LINK_RATE_UNKNOWN) {
 		uint32_t n_vid = 0x8000;
 		uint32_t m_vid;
+		uint32_t n_multiply = 0;
+		uint64_t m_vid_l = n_vid;
+
+		/* YCbCr 4:2:0 : Computed VID_M will be 2X the input rate */
+		if (param->pixel_encoding == PIXEL_ENCODING_YCBCR420)
+			n_multiply = 1;
 
 		/* M / N = Fstream / Flink
 		 * m_vid / n_vid = pixel rate / link rate
 		 */
 
-		uint64_t m_vid_l = n_vid;
-
 		m_vid_l *= param->pixel_clk_khz;
 		m_vid_l = div_u64(m_vid_l,
 			param->link_settings.link_rate
@@ -859,7 +862,9 @@ void enc1_stream_encoder_dp_unblank(
 
 		REG_UPDATE(DP_VID_M, DP_VID_M, m_vid);
 
-		REG_UPDATE(DP_VID_TIMING, DP_VID_M_N_GEN_EN, 1);
+		REG_UPDATE_2(DP_VID_TIMING,
+				DP_VID_M_N_GEN_EN, 1,
+				DP_VID_N_MUL, n_multiply);
 	}
 
 	/* set DIG_START to 0x1 to resync FIFO */

drivers/gpu/drm/amd/display/dc/inc/hw/stream_encoder.h

@@ -68,6 +68,7 @@ struct encoder_info_frame {
 struct encoder_unblank_param {
 	struct dc_link_settings link_settings;
 	unsigned int pixel_clk_khz;
+	enum dc_pixel_encoding pixel_encoding;
 };
 
 struct encoder_set_dp_phy_pattern_param {