From 4e450dfd0f968b79204637bf13280892dff287b1 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Thu, 5 Dec 2024 06:30:33 -0800 Subject: [PATCH] tty: serial: Work around warning backtrace in serial8250_set_defaults Commit 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") triggers warning backtraces on a number of platforms which don't support IO ports. WARNING: CPU: 0 PID: 0 at drivers/tty/serial/8250/8250_port.c:470 serial8250_set_defaults+0x148/0x1d8 Unsupported UART type 0 The problem is seen because serial8250_set_defaults() is called for all members of the serial8250_ports[] array even if that array is not initialized. Work around the problem by only displaying the warning if the port type is not 0 (UPIO_PORT) or if iobase is set for the port. Fixes: 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies") Acked-by: Arnd Bergmann Cc: Niklas Schnelle Signed-off-by: Guenter Roeck Tested-by: Stafford Horne Link: https://lore.kernel.org/r/20241205143033.2695333-1-linux@roeck-us.net Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_port.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 4d63d80e78a9..649e74e9b52f 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -467,7 +467,8 @@ static void set_io_from_upio(struct uart_port *p) break; #endif default: - WARN(1, "Unsupported UART type %x\n", p->iotype); + WARN(p->iotype != UPIO_PORT || p->iobase, + "Unsupported UART type %x\n", p->iotype); p->serial_in = no_serial_in; p->serial_out = no_serial_out; } -- 2.25.1