--- zzzz-none-000/linux-4.4.60/drivers/mmc/host/sdhci.c	2017-04-08 07:53:53.000000000 +0000
+++ dragonfly-4020-701/linux-4.4.60/drivers/mmc/host/sdhci.c	2018-11-08 13:36:17.000000000 +0000
@@ -942,8 +942,19 @@
 		}
 	}
 
-	if (data->flags & MMC_DATA_READ)
+	if (data->flags & MMC_DATA_READ) {
 		mode |= SDHCI_TRNS_READ;
+		if (host->ops->toggle_cdr) {
+			if ((cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200) ||
+					(cmd->opcode == MMC_SEND_TUNING_BLOCK))
+				host->ops->toggle_cdr(host, false);
+			else
+				host->ops->toggle_cdr(host, true);
+		}
+	}
+	if (host->ops->toggle_cdr && (data->flags & MMC_DATA_WRITE))
+		host->ops->toggle_cdr(host, false);
+
 	if (host->flags & SDHCI_REQ_USE_DMA)
 		mode |= SDHCI_TRNS_DMA;