[PATCH] Perle multimodem card (PCI-RAS) detection

[linux-2.6-omap-h63xx.git] / drivers / serial / 8250.c

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 5261f0af8b101bcf4e1149caebdb484bbe92aa70..2964ca9df5a010f9cebb264e4115d5a588e5c234 100644 (file)
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -920,12 +920,16 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags)
 #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) {
                        /*