Messages in this thread | | | Date | Mon, 26 Sep 2022 09:16:43 +0200 | Subject | Re: [PATCH] serial: 8250: Fix restoring termios speed after suspend | From | Jiri Slaby <> |
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On 24. 09. 22, 12:43, Pali Rohár wrote: > Since commit edc6afc54968 ("tty: switch to ktermios and new framework") > termios speed is no longer stored only in c_cflag member but also in new > additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag > then termios speed is stored only in these new members. > > Since commit 027b57170bf8 ("serial: core: Fix initializing and restoring > termios speed") termios speed is available also in struct console. > > So properly restore also c_ispeed and c_ospeed members after suspend to fix > restoring termios speed which is not represented by Bnnn constant. > > Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend") > Signed-off-by: Pali Rohár <pali@kernel.org> > --- > drivers/tty/serial/8250/8250_port.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index 39b35a61958c..441f317c55af 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -3314,8 +3314,13 @@ static void serial8250_console_restore(struct uart_8250_port *up) > unsigned int baud, quot, frac = 0; > > termios.c_cflag = port->cons->cflag; > - if (port->state->port.tty && termios.c_cflag == 0) > + termios.c_ispeed = port->cons->ispeed; > + termios.c_ospeed = port->cons->ospeed; > + if (port->state->port.tty && termios.c_cflag == 0) {
I don't currently know how safe it is to assume port->state->port.tty cannot change between the test above and the dereferences below.
In anyway, you should cache it as it is used 4 times now. It would make the code definitely more readable.
> termios.c_cflag = port->state->port.tty->termios.c_cflag; > + termios.c_ispeed = port->state->port.tty->termios.c_ispeed; > + termios.c_ospeed = port->state->port.tty->termios.c_ospeed; > + } > > baud = serial8250_get_baud_rate(port, &termios, NULL); > quot = serial8250_get_divisor(port, baud, &frac);
-- js suse labs
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