On Tue, 24 Jun 2025, Jiri Slaby (SUSE) wrote:
> The check for "port.type == PORT_8250_CIR" is present twice in
> serial8250_register_8250_port(). The latter was already tried to be
> dropped by 1104321a7b3b ("serial: Delete dead code for CIR serial
> ports") and then reverted by 9527b82ae3af ("Revert "serial: Delete dead
> code for CIR serial ports"").
>
> Document this weirdness with a reason.
>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
> Link: https://lore.kernel.org/all/aFcDOx1bdB34I5hS@surfacebook.localdomain/
> ---
> drivers/tty/serial/8250/8250_core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index a6ecb8575da4..feb920c5b2e8 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -717,6 +717,7 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
> nr_uarts++;
> }
>
> + /* Check if it is CIR already. We check this below again, see there why. */
> if (uart->port.type == PORT_8250_CIR) {
> ret = -ENODEV;
> goto unlock;
> @@ -815,6 +816,7 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
> if (up->dl_write)
> uart->dl_write = up->dl_write;
>
> + /* Check the type (again)! It might have changed by the port.type assignment above. */
> if (uart->port.type != PORT_8250_CIR) {
> if (uart_console_registered(&uart->port))
> pm_runtime_get_sync(uart->port.dev);
>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
--
i.