diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index cfda31a7edd6..f1366cf4e6a9 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -884,14 +884,12 @@ static void imx_rx_dma_done(struct imx_port *sport)
 }
 
 /*
- * There are three kinds of RX DMA interrupts(such as in the MX6Q):
+ * There are two kinds of RX DMA interrupts(such as in the MX6Q):
  *   [1] the RX DMA buffer is full.
- *   [2] the Aging timer expires(wait for 8 bytes long)
- *   [3] the Idle Condition Detect(enabled the UCR4_IDDMAEN).
+ *   [2] the aging timer expires
  *
- * The [2] is trigger when a character was been sitting in the FIFO
- * meanwhile [3] can wait for 32 bytes long when the RX line is
- * on IDLE state and RxFIFO is empty.
+ * Condition [2] is triggered when a character has been sitting in the FIFO
+ * for at least 8 byte durations.
  */
 static void dma_rx_callback(void *data)
 {
@@ -909,13 +907,6 @@ static void dma_rx_callback(void *data)
 	status = dmaengine_tx_status(chan, (dma_cookie_t)0, &state);
 	count = RX_BUF_SIZE - state.residue;
 
-	if (readl(sport->port.membase + USR2) & USR2_IDLE) {
-		/* In condition [3] the SDMA counted up too early */
-		count--;
-
-		writel(USR2_IDLE, sport->port.membase + USR2);
-	}
-
 	dev_dbg(sport->port.dev, "We get %d bytes.\n", count);
 
 	if (count) {
@@ -1072,20 +1063,13 @@ static void imx_enable_dma(struct imx_port *sport)
 
 	/* set UCR1 */
 	temp = readl(sport->port.membase + UCR1);
-	temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN |
-		/* wait for 32 idle frames for IDDMA interrupt */
-		UCR1_ICD_REG(3);
+	temp |= UCR1_RDMAEN | UCR1_TDMAEN | UCR1_ATDMAEN;
 	writel(temp, sport->port.membase + UCR1);
 
 	temp = readl(sport->port.membase + UCR2);
 	temp |= UCR2_ATEN;
 	writel(temp, sport->port.membase + UCR2);
 
-	/* set UCR4 */
-	temp = readl(sport->port.membase + UCR4);
-	temp |= UCR4_IDDMAEN;
-	writel(temp, sport->port.membase + UCR4);
-
 	imx_setup_ufcr(sport, TXTL_DMA, RXTL_DMA);
 
 	sport->dma_is_enabled = 1;
@@ -1105,11 +1089,6 @@ static void imx_disable_dma(struct imx_port *sport)
 	temp &= ~(UCR2_CTSC | UCR2_CTS | UCR2_ATEN);
 	writel(temp, sport->port.membase + UCR2);
 
-	/* clear UCR4 */
-	temp = readl(sport->port.membase + UCR4);
-	temp &= ~UCR4_IDDMAEN;
-	writel(temp, sport->port.membase + UCR4);
-
 	imx_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT);
 
 	sport->dma_is_enabled = 0;