drm/amd/display: Backup and restore plane configuration only on update

[WHY&HOW]
When backing up and restoring plane states for minimal transition
cases, only configuration should be backed up and restored. Information
only relevant to the object/allocation (like refcount) should be
excluded. Also move this interface to dc_plane.h.

Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Dillon Varone <Dillon.Varone@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -36,6 +36,7 @@
 #include "resource.h"
 #include "dc_state.h"
 #include "dc_state_priv.h"
+#include "dc_plane.h"
 #include "dc_plane_priv.h"
 #include "dc_stream_priv.h"
 
@@ -3320,7 +3321,7 @@ static void backup_planes_and_stream_state(
 		return;
 
 	for (i = 0; i < status->plane_count; i++) {
-		scratch->plane_states[i] = *status->plane_states[i];
+		dc_plane_copy_config(&scratch->plane_states[i], status->plane_states[i]);
 	}
 	scratch->stream_state = *stream;
 }
@@ -3336,10 +3337,7 @@ static void restore_planes_and_stream_state(
 		return;
 
 	for (i = 0; i < status->plane_count; i++) {
-		/* refcount will always be valid, restore everything else */
-		struct kref refcount = status->plane_states[i]->refcount;
-		*status->plane_states[i] = scratch->plane_states[i];
-		status->plane_states[i]->refcount = refcount;
+		dc_plane_copy_config(status->plane_states[i], &scratch->plane_states[i]);
 	}
 	*stream = scratch->stream_state;
 }

drivers/gpu/drm/amd/display/dc/core/dc_surface.c

@@ -294,3 +294,17 @@ void dc_plane_force_dcc_and_tiling_disable(struct dc_plane_state *plane_state,
 			dc->hwss.clear_surface_dcc_and_tiling(pipe_ctx, plane_state, clear_tiling);
 	}
 }
+
+void dc_plane_copy_config(struct dc_plane_state *dst, const struct dc_plane_state *src)
+{
+	struct kref temp_refcount;
+
+	/* backup persistent info */
+	memcpy(&temp_refcount, &dst->refcount, sizeof(struct kref));
+
+	/* copy all configuration information */
+	memcpy(dst, src, sizeof(struct dc_plane_state));
+
+	/* restore persistent info */
+	memcpy(&dst->refcount, &temp_refcount, sizeof(struct kref));
+}

drivers/gpu/drm/amd/display/dc/dc_plane.h

@@ -37,4 +37,7 @@ void dc_plane_state_release(struct dc_plane_state *plane_state);
 void dc_plane_force_dcc_and_tiling_disable(struct dc_plane_state *plane_state,
 					   bool clear_tiling);
 
+
+void dc_plane_copy_config(struct dc_plane_state *dst, const struct dc_plane_state *src);
+
 #endif /* _DC_PLANE_H_ */