śr., 1 mar 2023 o 09:39 Greg Kroah-Hartman gregkh@linuxfoundation.org napisał(a):
On Wed, Mar 01, 2023 at 08:57:51AM +0100, Lukasz Majczak wrote:
Re-enable the console device after suspending, causes its cflags, ispeed and ospeed to be set anew, basing on the values stored in uport->cons. The issue is that these values are set only once, when parsing console parameters after boot (see uart_set_options()), next after configuring a port in uart_port_startup() these parameteres (cflags, ispeed and ospeed) are copied to termios structure and the orginal one (stored in uport->cons) are cleared, but there is no place in code where those fields are checked against 0. When kernel calls uart_resume_port() and setups console, it copies cflags, ispeed and ospeed values from uart->cons,but those are alread cleared. The efect is that console is broken. This patch address this by preserving the cflags, ispeed and ospeed fields in uart->cons during uart_port_startup().
Signed-off-by: Lukasz Majczak lma@semihalf.com Cc: stable@vger.kernel.org
drivers/tty/serial/serial_core.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 2bd32c8ece39..394a05c09d87 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -225,9 +225,6 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state, tty->termios.c_cflag = uport->cons->cflag; tty->termios.c_ispeed = uport->cons->ispeed; tty->termios.c_ospeed = uport->cons->ospeed;
uport->cons->cflag = 0;uport->cons->ispeed = 0;uport->cons->ospeed = 0; } /* * Initialise the hardware port settings.-- 2.39.2.722.g9855ee24e9-goog
What commit id does this fix?
thanks,
greg k-h
Hi Greg,
There are actually two commits that introduce problematic uport flags clearing in uart_startup (for the sake of simplicity I'd ignore the older history): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h... https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h... It's 10 years between those 2 and to me it was hard to decide about picking a proper one for the `Fixes:` tag. How would you recommend to proceed wrt applying this patch on the stable releases?
Best regards, Lukasz