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From 8936e50f62c8d5bad3a23e079db430fe93569357 Mon Sep 17 00:00:00 2001
From: Eric Yang <Eric.Yang2@amd.com>
Date: Fri, 23 Mar 2018 13:56:16 -0400
Subject: [PATCH 4007/4131] drm/amd/display: fix link bw calculation for 422
and 420 encoding
Link bw required is reduced when we have chroma subsampling.
Signed-off-by: Eric Yang <Eric.Yang2@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 53 ++++++++++++++----------
1 file changed, 32 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index e103ce8e..a6dcd42 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -1378,37 +1378,48 @@ static uint32_t bandwidth_in_kbps_from_timing(
{
uint32_t bits_per_channel = 0;
uint32_t kbps;
- switch (timing->display_color_depth) {
- case COLOR_DEPTH_666:
- bits_per_channel = 6;
- break;
- case COLOR_DEPTH_888:
- bits_per_channel = 8;
- break;
- case COLOR_DEPTH_101010:
- bits_per_channel = 10;
- break;
- case COLOR_DEPTH_121212:
+ if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR422)
bits_per_channel = 12;
- break;
- case COLOR_DEPTH_141414:
- bits_per_channel = 14;
- break;
- case COLOR_DEPTH_161616:
- bits_per_channel = 16;
- break;
- default:
- break;
+ else{
+
+ switch (timing->display_color_depth) {
+
+ case COLOR_DEPTH_666:
+ bits_per_channel = 6;
+ break;
+ case COLOR_DEPTH_888:
+ bits_per_channel = 8;
+ break;
+ case COLOR_DEPTH_101010:
+ bits_per_channel = 10;
+ break;
+ case COLOR_DEPTH_121212:
+ bits_per_channel = 12;
+ break;
+ case COLOR_DEPTH_141414:
+ bits_per_channel = 14;
+ break;
+ case COLOR_DEPTH_161616:
+ bits_per_channel = 16;
+ break;
+ default:
+ break;
+ }
}
ASSERT(bits_per_channel != 0);
kbps = timing->pix_clk_khz;
kbps *= bits_per_channel;
- if (timing->flags.Y_ONLY != 1)
+ if (timing->flags.Y_ONLY != 1) {
/*Only YOnly make reduce bandwidth by 1/3 compares to RGB*/
kbps *= 3;
+ if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR420)
+ kbps /= 2;
+ else if (timing->pixel_encoding == PIXEL_ENCODING_YCBCR422)
+ kbps = kbps * 2 / 3;
+ }
return kbps;
--
2.7.4
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