This is a note to let you know that I've just added the patch titled

MIPS: AR7: ensure the port type's FCR value is used

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: mips-ar7-ensure-the-port-type-s-fcr-value-is-used.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 0a5191efe06b5103909206e4fbcff81d30283f8e Mon Sep 17 00:00:00 2001

From: Jonas Gorski jonas.gorski@gmail.com Date: Sun, 29 Oct 2017 16:27:21 +0100 Subject: MIPS: AR7: ensure the port type's FCR value is used

From: Jonas Gorski jonas.gorski@gmail.com

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@gmail.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Yoshihiro YUNOMAE yoshihiro.yunomae.ez@hitachi.com Cc: Florian Fainelli f.fainelli@gmail.com Cc: Nicolas Schichan nschichan@freebox.fr Cc: linux-mips@linux-mips.org Cc: linux-serial@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17544/ Signed-off-by: Ralf Baechle ralf@linux-mips.org Cc: James Hogan jhogan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- 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 @@ -576,7 +576,7 @@ 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;

Patches currently in stable-queue which might be from jonas.gorski@gmail.com are

queue-4.9/mips-ar7-ensure-the-port-type-s-fcr-value-is-used.patch