drm/amd/display: fix resource saving missing when power state switch

Signed-off-by: Tao.Huang <Tao.Huang@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1930,6 +1930,12 @@ void dc_set_power_state(
 	enum dc_acpi_cm_power_state power_state)
 {
 	struct kref refcount;
+	struct display_mode_lib *dml = kzalloc(sizeof(struct display_mode_lib),
+						GFP_KERNEL);
+
+	ASSERT(dml);
+	if (!dml)
+		return;
 
 	switch (power_state) {
 	case DC_ACPI_CM_POWER_STATE_D0:
@@ -1946,15 +1952,20 @@ void dc_set_power_state(
 
 		/* Preserve refcount */
 		refcount = dc->current_state->refcount;
+		/* Preserve display mode lib */
+		memcpy(dml, &dc->current_state->bw_ctx.dml, sizeof(struct display_mode_lib));
+
 		dc_resource_state_destruct(dc->current_state);
 		memset(dc->current_state, 0,
 				sizeof(*dc->current_state));
 
 		dc->current_state->refcount = refcount;
+		dc->current_state->bw_ctx.dml = *dml;
 
 		break;
 	}
 
+	kfree(dml);
 }
 
 void dc_resume(struct dc *dc)