> On Thu, Aug 04, 2022 at 03:04:20PM +0800, Sherry Sun wrote:
> > When the user initializes the uart port, and waits for the transmit
> > engine to complete in lpuart32_set_termios(), if the UART TX fifo has
> > dirty data and the UARTMODIR enable the flow control, the TX fifo may
> > never be empty. So here we should disable the flow control first to
> > make sure the transmit engin can complete.
> >
> > Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
> > ---
> > Changes in V2:
> > 1. Rephrase the commit log as suggested by Jiri.
> > ---
> > drivers/tty/serial/fsl_lpuart.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/tty/serial/fsl_lpuart.c
> > b/drivers/tty/serial/fsl_lpuart.c index fc7d235a1e27..f0fccd2ff7ac
> > 100644
> > --- a/drivers/tty/serial/fsl_lpuart.c
> > +++ b/drivers/tty/serial/fsl_lpuart.c
> > @@ -2172,6 +2172,7 @@ lpuart32_set_termios(struct uart_port *port,
> struct ktermios *termios,
> > uart_update_timeout(port, termios->c_cflag, baud);
> >
> > /* wait transmit engin complete */
> > + lpuart32_write(&sport->port, 0, UARTMODIR);
> > lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC);
> >
> > /* disable transmit and receive */
> > --
> > 2.17.1
>
> What commit id does this fix? Should it be backported to older stable kernels?
This issue existed when the lpuart32_set_termios() was introduced. So the Fixes tag should be:
Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support"), and I believe it can be backported to the older stable kernels.
Should I send a V2 patch to add the Fixes tag?
Best regards
Sherry
>
> thanks,
>
> greg k-h
