Re: [PATCH] serial: Fix an invalid comparing statement

[Sugaya, Taichi]

Hi,

On 2019/06/11 1:56, Greg Kroah-Hartman wrote:
> On Mon, May 27, 2019 at 02:01:27PM +0900, Sugaya Taichi wrote:
> > Drop the if-statement which refers to 8th bit field of u8 variable.
> > The bit field is no longer used.
> >
> > Fixes: ba44dc043004 ("serial: Add Milbeaut serial control")
> > Reported-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > Signed-off-by: Sugaya Taichi <sugaya.taichi@xxxxxxxxxxxxx>
> > ---
> >   drivers/tty/serial/milbeaut_usio.c | 15 +++++----------
> >   1 file changed, 5 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/tty/serial/milbeaut_usio.c b/drivers/tty/serial/milbeaut_usio.c
> > index 949ab7e..d7207ab 100644
> > --- a/drivers/tty/serial/milbeaut_usio.c
> > +++ b/drivers/tty/serial/milbeaut_usio.c
> > @@ -56,7 +56,6 @@
> >   #define MLB_USIO_SSR_FRE		BIT(4)
> >   #define MLB_USIO_SSR_PE			BIT(5)
> >   #define MLB_USIO_SSR_REC		BIT(7)
> > -#define MLB_USIO_SSR_BRK		BIT(8)
> >   #define MLB_USIO_FCR_FE1		BIT(0)
> >   #define MLB_USIO_FCR_FE2		BIT(1)
> >   #define MLB_USIO_FCR_FCL1		BIT(2)
> > @@ -180,18 +179,14 @@ static void mlb_usio_rx_chars(struct uart_port *port)
> >   		if (status & MLB_USIO_SSR_ORE)
> >   			port->icount.overrun++;
> >   		status &= port->read_status_mask;
> > -		if (status & MLB_USIO_SSR_BRK) {
> > -			flag = TTY_BREAK;
> > +		if (status & MLB_USIO_SSR_PE) {
> > +			flag = TTY_PARITY;
> >   			ch = 0;
> >   		} else
> > -			if (status & MLB_USIO_SSR_PE) {
> > -				flag = TTY_PARITY;
> > +			if (status & MLB_USIO_SSR_FRE) {
> > +				flag = TTY_FRAME;
> >   				ch = 0;
> > -			} else
> > -				if (status & MLB_USIO_SSR_FRE) {
> > -					flag = TTY_FRAME;
> > -					ch = 0;
> > -				}
> > +			}
> >   		if (flag)
> >   			uart_insert_char(port, status, MLB_USIO_SSR_ORE,
> >   					 ch, flag);
>
> While the code never actually supported Break, you are explicitly
> removing that logic now.  So shouldn't you instead _fix_ break handling?
> The code before and after your change does not work any differently, so
> this patch isn't really needed at this point.

According to research, MLB_USIO_SSR_BRK was a remnant of old HW.
Since current one does not handle the Break, all logic related it should be
removed. I try to make a new fix patch.

Thanks,
Sugaya Taichi

> thanks,
>
> greg k-h