diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 5261f0a..2964ca9 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -920,12 +920,16 @@
 #ifdef __i386__
 		outb(0xff, 0x080);
 #endif
-		scratch2 = serial_inp(up, UART_IER);
+		/*
+		 * Mask out IER[7:4] bits for test as some UARTs (e.g. TL
+		 * 16C754B) allow only to modify them if an EFR bit is set.
+		 */
+		scratch2 = serial_inp(up, UART_IER) & 0x0f;
 		serial_outp(up, UART_IER, 0x0F);
 #ifdef __i386__
 		outb(0, 0x080);
 #endif
-		scratch3 = serial_inp(up, UART_IER);
+		scratch3 = serial_inp(up, UART_IER) & 0x0f;
 		serial_outp(up, UART_IER, scratch);
 		if (scratch2 != 0 || scratch3 != 0x0F) {
 			/*
diff --git a/drivers/serial/8250_pci.c b/drivers/serial/8250_pci.c
index 52e2e64..5dfaa09 100644
--- a/drivers/serial/8250_pci.c
+++ b/drivers/serial/8250_pci.c
@@ -679,6 +679,13 @@
 	 */
 	{
 		.vendor		= PCI_VENDOR_ID_PLX,
+		.device		= PCI_DEVICE_ID_PLX_9030,
+		.subvendor	= PCI_SUBVENDOR_ID_PERLE,
+		.subdevice	= PCI_ANY_ID,
+		.setup		= pci_default_setup,
+	},
+	{
+		.vendor		= PCI_VENDOR_ID_PLX,
 		.device		= PCI_DEVICE_ID_PLX_9050,
 		.subvendor	= PCI_SUBVENDOR_ID_EXSYS,
 		.subdevice	= PCI_SUBDEVICE_ID_EXSYS_4055,
@@ -2379,6 +2386,15 @@
 		pbn_b2_2_115200 },
 
 	/*
+	 * Perle PCI-RAS cards
+	 */
+	{       PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9030,
+		PCI_SUBVENDOR_ID_PERLE, PCI_SUBDEVICE_ID_PCI_RAS4,
+		0, 0, pbn_b2_4_921600 },
+	{       PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9030,
+		PCI_SUBVENDOR_ID_PERLE, PCI_SUBDEVICE_ID_PCI_RAS8,
+		0, 0, pbn_b2_8_921600 },
+	/*
 	 * These entries match devices with class COMMUNICATION_SERIAL,
 	 * COMMUNICATION_MODEM or COMMUNICATION_MULTISERIAL
 	 */