3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jonas Gorski <jonas.gorski@xxxxxxxxx> 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 ers [kee 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 <jonas.gorski@xxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@xxxxxxxxxxx> Cc: Florian Fainelli <f.fainelli@xxxxxxxxx> Cc: Nicolas Schichan <nschichan@xxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Cc: linux-serial@xxxxxxxxxxxxxxx Patchwork: https://patchwork.linux-mips.org/patch/17544/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: James Hogan <jhogan@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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; -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html