From: "Leo (Sunpeng) Li" <sunpeng.li@amd.com>
Date: Fri, 10 Nov 2017 15:02:19 -0500
Subject: drm/amd/display: Do DC mode-change check when adding CRTCs
Git-commit: 8ffca5dca093cdd25264e782cc0c4539cb318925
Patch-mainline: v4.15-rc2
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Within atomic check, dm_update_crtcs_state is called twice. First to
remove from the dc_state, and subsequently to add to it.

In both calls, a secondary mode-change check is done using dc-level
states. We shouldn't be doing this while removing, since a new
dc_stream_state has not been created to do the necessary comparison.
Because of this, the mode_changed flag within the DRM state can be
mistakenly set to false. Doing so only when adding prevents this.

We are also guaranteed that a call to add will come after remove, or
else the atomic check fails (and a commit will not happen).

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@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/amdgpu_dm/amdgpu_dm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4460,7 +4460,7 @@ static int dm_update_crtcs_state(struct
 			}
 		}
 
-		if (dc_is_stream_unchanged(new_stream, dm_old_crtc_state->stream) &&
+		if (enable && dc_is_stream_unchanged(new_stream, dm_old_crtc_state->stream) &&
 				dc_is_stream_scaling_unchanged(new_stream, dm_old_crtc_state->stream)) {
 
 			new_crtc_state->mode_changed = false;