Commit b5b82df6, from May 2007, breaks no_console_suspend on the OLPC XO laptop. Basically what happens is that upon returning from resume, serial8250_resume_port() will reconfigure the port for high speed mode and all console output will be garbled, making debug of the resume path painful. This patch modifies serial8250_resume_port() to not touch the port in the case where it is the console port and console suspend is disabled. Signed-off-by: Deepak Saxena <dsaxena@xxxxxxxxxx> --- The OLPC tree has been carrying a workaround for about two years but this patch is not the version we've been using. That one can be found at http://dev.laptop.org/~dsaxena/patches/console_suspend_old.patch. I prefer the approach of handling this in the 8250 driver itself. diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index b4b3981..d4b6373 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -2887,7 +2887,8 @@ void serial8250_resume_port(int line) { struct uart_8250_port *up = &serial8250_ports[line]; - if (up->capabilities & UART_NATSEMI) { + if ((up->capabilities & UART_NATSEMI) && + (!uart_console(&up->port) && console_suspend_enabled)) { unsigned char tmp; /* Ensure it's still in high speed mode */ diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index b0bb29d..05fd868 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -54,12 +54,6 @@ static struct lock_class_key port_lock_key; #define uart_users(state) ((state)->count + (state)->info.port.blocked_open) -#ifdef CONFIG_SERIAL_CORE_CONSOLE -#define uart_console(port) ((port)->cons && (port)->cons->index == (port)->line) -#else -#define uart_console(port) (0) -#endif - static void uart_change_speed(struct uart_state *state, struct ktermios *old_termios); static void uart_wait_until_sent(struct tty_struct *tty, int timeout); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 57a97e5..9fba77a 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -427,6 +427,12 @@ struct tty_driver *uart_console_device(struct console *co, int *index); void uart_console_write(struct uart_port *port, const char *s, unsigned int count, void (*putchar)(struct uart_port *, int)); +#ifdef CONFIG_SERIAL_CORE_CONSOLE +#define uart_console(port) ((port)->cons && (port)->cons->index == (port)->line) +#else +#define uart_console(port) (0) +#endif + /* * Port/driver registration/removal -- In the end, they will not say, "those were dark times," they will ask "why were their poets silent?" - Bertold Brecht -- 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
