[PATCH 15/33] drm/amd/display: Update 128b/132b downspread factor to 0.3%

Alan Liu HaoPing.Liu at amd.com
Wed Jul 12 17:11:19 UTC 2023


From: George Shen <george.shen at amd.com>

[Why]
Updating downspread factor to 0.3% to add additional margin to account
for potential link rate deviations (up to 300ppm as per the DP spec).

Reviewed-by: Wenjing Liu <wenjing.liu at amd.com>
Acked-by: Alan Liu <haoping.liu at amd.com>
Signed-off-by: George Shen <george.shen at amd.com>
---
 drivers/gpu/drm/amd/display/include/link_service_types.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/include/link_service_types.h b/drivers/gpu/drm/amd/display/include/link_service_types.h
index cd870af5fd25..1b8ab20f1715 100644
--- a/drivers/gpu/drm/amd/display/include/link_service_types.h
+++ b/drivers/gpu/drm/amd/display/include/link_service_types.h
@@ -53,7 +53,7 @@ enum {
 	BITS_PER_DP_BYTE = 10,
 	DATA_EFFICIENCY_8b_10b_x10000 = 8000, /* 80% data efficiency */
 	DATA_EFFICIENCY_8b_10b_FEC_EFFICIENCY_x100 = 97, /* 97% data efficiency when FEC is enabled */
-	DATA_EFFICIENCY_128b_132b_x10000 = 9646, /* 96.71% data efficiency x 99.75% downspread factor */
+	DATA_EFFICIENCY_128b_132b_x10000 = 9641, /* 96.71% data efficiency x 99.7% downspread factor */
 };
 
 enum lttpr_mode {
-- 
2.34.1



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