On Sun, Aug 21, 2022 at 10:01:45AM +0000, Sherry Sun wrote:
> > 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?
Yes please.
