[PATCH 1/9] drm/amd/display: Add a left edge pixel if in YCbCr422 or YCbCr420 and odm

[Alex Hung]

From: Peterson Guo <peterson.guo at amd.com>

[WHY]
On some cards when odm is used, the monitor will have 2 separate pipes
split vertically. When compression is used on the YCbCr colour space on
the second pipe to have correct colours, we need to read a pixel from the
end of first pipe to accurately display colours. Hardware was programmed
properly to account for this extra pixel but it was not calculated
properly in software causing a split screen on some monitors.

[HOW]
The fix adjusts the second pipe's viewport and timings if the pixel
encoding is YCbCr422 or YCbCr420.

Cc: Mario Limonciello <mario.limonciello at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at vger.kernel.org
Reviewed-by: George Shen <george.shen at amd.com>
Signed-off-by: Peterson Guo <peterson.guo at amd.com>
Signed-off-by: Alex Hung <alex.hung at amd.com>
---
 .../dc/resource/dcn20/dcn20_resource.c        | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn20/dcn20_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn20/dcn20_resource.c
index 189d0c85872e..7a5b9aa5292c 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn20/dcn20_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn20/dcn20_resource.c
@@ -1510,6 +1510,7 @@ bool dcn20_split_stream_for_odm(
 
 	if (prev_odm_pipe->plane_state) {
 		struct scaler_data *sd = &prev_odm_pipe->plane_res.scl_data;
+		struct output_pixel_processor *opp = next_odm_pipe->stream_res.opp;
 		int new_width;
 
 		/* HACTIVE halved for odm combine */
@@ -1543,7 +1544,28 @@ bool dcn20_split_stream_for_odm(
 		sd->viewport_c.x += dc_fixpt_floor(dc_fixpt_mul_int(
 				sd->ratios.horz_c, sd->h_active - sd->recout.x));
 		sd->recout.x = 0;
+
+		/*
+		 * When odm is used in YcbCr422 or 420 colour space, a split screen
+		 * will be seen with the previous calculations since the extra left
+		 *  edge pixel is accounted for in fmt but not in viewport.
+		 *
+		 * Below are calculations which fix the split by fixing the calculations
+		 * if there is an extra left edge pixel.
+		 */
+		if (opp && opp->funcs->opp_get_left_edge_extra_pixel_count
+				&& opp->funcs->opp_get_left_edge_extra_pixel_count(
+					opp, next_odm_pipe->stream->timing.pixel_encoding,
+					resource_is_pipe_type(next_odm_pipe, OTG_MASTER)) == 1) {
+			sd->h_active += 1;
+			sd->recout.width += 1;
+			sd->viewport.x -= dc_fixpt_ceil(dc_fixpt_mul_int(sd->ratios.horz, 1));
+			sd->viewport_c.x -= dc_fixpt_ceil(dc_fixpt_mul_int(sd->ratios.horz, 1));
+			sd->viewport_c.width += dc_fixpt_ceil(dc_fixpt_mul_int(sd->ratios.horz, 1));
+			sd->viewport.width += dc_fixpt_ceil(dc_fixpt_mul_int(sd->ratios.horz, 1));
+		}
 	}
+
 	if (!next_odm_pipe->top_pipe)
 		next_odm_pipe->stream_res.opp = pool->opps[next_odm_pipe->pipe_idx];
 	else
@@ -2132,6 +2154,7 @@ bool dcn20_fast_validate_bw(
 			ASSERT(0);
 		}
 	}
+
 	/* Actual dsc count per stream dsc validation*/
 	if (!dcn20_validate_dsc(dc, context)) {
 		context->bw_ctx.dml.vba.ValidationStatus[context->bw_ctx.dml.vba.soc.num_states] =
-- 
2.43.0