From f9c3ad9cf9ffb05ce4f2b0ea5f58f81415594c57 Mon Sep 17 00:00:00 2001 From: Yongqiang Sun Date: Wed, 9 Mar 2016 14:56:16 -0500 Subject: [PATCH 0893/1110] drm/amd/dal: Fixed DP passive dongle not light up issue Signed-off-by: Yongqiang Sun Acked-by: Harry Wentland Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/dal/dc/core/dc_link.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/dal/dc/core/dc_link.c b/drivers/gpu/drm/amd/dal/dc/core/dc_link.c index 0232956..fd406f9 100644 --- a/drivers/gpu/drm/amd/dal/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/dal/dc/core/dc_link.c @@ -99,7 +99,13 @@ static bool program_hpd_filter( case SIGNAL_TYPE_DISPLAY_PORT: case SIGNAL_TYPE_DISPLAY_PORT_MST: /* Program hpd filter to allow DP signal to settle */ - delay_on_connect_in_ms = 20; + /* 500: not able to detect MST <-> SST switch as HPD is low for + * only 100ms on DELL U2413 + * 0: some passive dongle still show aux mode instead of i2c + * 20-50:not enough to hide bouncing HPD with passive dongle. + * also see intermittent i2c read issues. + */ + delay_on_connect_in_ms = 80; delay_on_disconnect_in_ms = 0; break; case SIGNAL_TYPE_LVDS: -- 2.7.4