Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> writes:
> On Fri, Jul 19, 2019 at 06:13:52PM +0300, Sergey Organov wrote:
>> Hello Uwe,
>>
>> Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> writes:
>> > Hello Sergey,
>> >
>> > On Fri, Jul 19, 2019 at 03:18:13PM +0300, Sergey Organov wrote:
>> >> Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> writes:
>> >> > On Fri, Jul 19, 2019 at 11:47:52AM +0300, Sergey Organov wrote:
>> >> >> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
>> >> >> index 57d6e6b..95d7984 100644
>> >> >> --- a/drivers/tty/serial/imx.c
>> >> >> +++ b/drivers/tty/serial/imx.c
>> >> >> @@ -405,7 +405,8 @@ static void imx_uart_rts_inactive(struct imx_port *sport, u32 *ucr2)
>> >> >> /* called with port.lock taken and irqs caller dependent */
>> >> >> static void imx_uart_rts_auto(struct imx_port *sport, u32 *ucr2)
>> >> >> {
>> >> >> - *ucr2 |= UCR2_CTSC;
>> >> >> + if (*ucr2 & UCR2_CTS)
>> >> >> + *ucr2 |= UCR2_CTSC;
>> >> >
>> >> > I think this patch is wrong or the commit log is insufficient.
>> >> > imx_uart_rts_auto() has only a single caller and there ucr2 & UCR2_CTS is
>> >> > never true. And CTSC isn't restored anywhere, is it?
>> >>
>> >> This is rebase to 'tty-next' branch, and you need to look at it in that
>> >> context. There, ucr2 & UCR2_CTS does already make sense, due to previous
>> >> fix that is already there.
>> >
>> > I looked at 57d6e6b which is the file you patched. And there
>> > imx_uart_rts_auto is only ever called with *ucr2 not having UCR2_CTS.
>> >
>> > If you still think I'm wrong, please improve the commit log
>> > accordingly.
>>
>> I still think you are wrong, but I don't know how to improve commit log.
>>
>> To check it once again, I just did:
>>
>> $ git show 57d6e6b > imx.c
>>
>> There, in imx_uart_set_termios(), I see:
>>
>> 1569: old_ucr2 = imx_uart_readl(sport, UCR2);
>> 1570: ucr2 = old_ucr2 & (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN | UCR2_CTS);
>>
>> Here, current UCR2 value is read into 'old_ucr2' and then its /current/
>> UCR2_CTS bit is copied into 'ucr2' (along with 3 other bits).
>>
>> Then, later in the same function:
>>
>> 1591: imx_uart_rts_auto(sport, &ucr2);
>>
>> is called that can check /current/ state of UCR2_CTS bit in '*ucr2'.
>>
>> That's what the patch does, checks this bit.
>>
>> Sorry, I fail to see how you came to conclusion that "*ucr2 not having
>> UCR2_CTS". Do we maybe still read different versions of the file?
>
> No, it's just that I failed to see that UCR2_CTS is in the set of bits
> that are retained even when looking twice :-|
Ah, that one... How familiar :-)
> So you convinced me that you are right and if you update the commit log
> as agreed already before and even add a comment in imx_uart_rts_auto
> along the lines of
>
> /*
> * Only let the receiver control RTS output if we were not
> * requested to have RTS inactive (which then should take
> * precedence).
> */
>
> you can have my Ack.
OK, will do
Thanks!
-- Sergey
