From: Eric Yang <Eric.Yang2@xxxxxxx>
Link bw required is reduced when we have chroma subsampling.
Signed-off-by: Eric Yang <Eric.Yang2 at amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu at amd.com>
Acked-by: Harry Wentland <harry.wentland at 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 e103ce8e0558..a6dcd4246c20 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;
--
2.15.1
