From: Tao <xtao@amd.com>
Date: Thu, 8 Feb 2018 16:04:25 -0500
Subject: drm/amd/display: Set vsc pack revision when DPCD revision is >= 1.2
Git-commit: 3b94a4007dcfd4ac5780cd3d8a2d99979c966073
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Brightness couldn't change when booting up in DC mode.
It was because "psr_enabled" flag was not set to true before
setting vsc packet revision, causing packet rev setup was skipped.
Now instead of checking the psr flag, it checks if the DPCD_REV >= 1.2
and set the vsc packet revision.

Signed-off-by: Tao <xtao@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_resource.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -35,6 +35,7 @@
 #include "core_types.h"
 #include "set_mode_types.h"
 #include "virtual/virtual_stream_encoder.h"
+#include "dpcd_defs.h"
 
 #include "dce80/dce80_resource.h"
 #include "dce100/dce100_resource.h"
@@ -2434,7 +2435,8 @@ static void set_vsc_info_packet(
 	unsigned int vscPacketRevision = 0;
 	unsigned int i;
 
-	if (stream->sink->link->psr_enabled) {
+	/*VSC packet set to 2 when DP revision >= 1.2*/
+	if (stream->sink->link->dpcd_caps.dpcd_rev.raw >= DPCD_REV_12) {
 		vscPacketRevision = 2;
 	}