From: Jonas Gorski jonas.gorski@gmail.com
This patch has been added to the 4.1 stable tree. If you have any objections, please let us know.
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[ Upstream commit 0a5191efe06b5103909206e4fbcff81d30283f8e ]
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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- arch/mips/ar7/platform.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/ar7/platform.c b/arch/mips/ar7/platform.c index 5afbb7b41160..d60986fdc288 100644 --- a/arch/mips/ar7/platform.c +++ b/arch/mips/ar7/platform.c @@ -577,7 +577,7 @@ static int __init ar7_register_uarts(void) 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;