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From ee6c9d41de084b2cefd90e5e0c9f30a35f6d3967 Mon Sep 17 00:00:00 2001
From: Jonas Gorski <jonas.gorski@gmail.com>
Date: Sun, 29 Oct 2017 15:50:42 +0100
Subject: [PATCH RFC 3/3] MIPS: AR7: ensure the port type's FCR value is used
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>
---
I'm not sure if this is just AR7's issue, or if this points to a general
issue for UARTs used as kernel console and login console with the "fixed"
commit.
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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