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Subject[PATCH 3.18 19/52] MIPS: AR7: ensure the port types FCR value is used
3.18-stable review patch.  If anyone has any objections, please let me know.


From: Jonas Gorski <>

commit 0a5191efe06b5103909206e4fbcff81d30283f8e upstream.

Since commit aef9a7bd9b67 ("serial/uart/8250: Add tunable RX interrupt
trigger I/F of FIFO buffers"), the port's default FCR value isn't used
in serial8250_do_set_termios anymore, but copied over once in
serial8250_config_port and then modified as needed.

Unfortunately, serial8250_config_port will never be called if the port
is shared between kernel and userspace, and the port's flag doesn't have
UPF_BOOT_AUTOCONF, which would trigger a serial8250_config_port as well.

This causes garbled output from userspace:

[ 5.220000] random: procd urandom read with 49 bits of entropy available

Fix this by forcing it to be configured on boot, resulting in the
expected output:

[ 5.250000] random: procd urandom read with 50 bits of entropy available
Press the [f] key and hit [enter] to enter failsafe mode
Press the [1], [2], [3] or [4] key and hit [enter] to select the debug level

Fixes: aef9a7bd9b67 ("serial/uart/8250: Add tunable RX interrupt trigger I/F of FIFO buffers")
Signed-off-by: Jonas Gorski <>
Cc: Greg Kroah-Hartman <>
Cc: Yoshihiro YUNOMAE <>
Cc: Florian Fainelli <>
Cc: Nicolas Schichan <>
Signed-off-by: Ralf Baechle <>
Cc: James Hogan <>
Signed-off-by: Greg Kroah-Hartman <>

arch/mips/ar7/platform.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/ar7/platform.c
+++ b/arch/mips/ar7/platform.c
@@ -581,7 +581,7 @@ static int __init ar7_register_uarts(voi
uart_port.type = PORT_AR7;
uart_port.uartclk = clk_get_rate(bus_clk) / 2;
uart_port.iotype = UPIO_MEM32;
- uart_port.flags = UPF_FIXED_TYPE;
+ uart_port.flags = UPF_FIXED_TYPE | UPF_BOOT_AUTOCONF;
uart_port.regshift = 2;

uart_port.line = 0;

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