diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 3765e2f4ad98a87dc44a98da7b225a41ad767716..c9cacd4d5b22f7c6bef9f5c5b47b4dac05b6c019 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1394,6 +1394,10 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
 	} else if (host->variant->busy_timeout && busy_resp &&
 		   status & MCI_DATATIMEOUT) {
 		cmd->error = -ETIMEDOUT;
+		/*
+		 * This will wake up mmci_irq_thread() which will issue
+		 * a hardware reset of the MMCI block.
+		 */
 		host->irq_action = IRQ_WAKE_THREAD;
 	} else {
 		cmd->resp[0] = readl(base + MMCIRESPONSE0);