[PATCH 4.16 244/272] drm/amd/display: Set vsc pack revision when DPCD revision is >= 1.2

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tao <xtao@xxxxxxx>

[ Upstream commit 3b94a4007dcfd4ac5780cd3d8a2d99979c966073 ]

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@xxxxxxx>
Reviewed-by: Tony Cheng <Tony.Cheng@xxxxxxx>
Acked-by: Harry Wentland <harry.wentland@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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"
@@ -2428,7 +2429,8 @@ 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;
 	}