Re: [PATCH 4/4] serial: sh-sci: Stop RX FIFO timer during port shutdown
On Mon, Jul 2, 2018 at 9:01 PM Rob Landley wrote:
> On 07/02/2018 04:50 AM, Geert Uytterhoeven wrote:
> > On Sun, Jul 1, 2018 at 7:27 PM Rob Landley wrote:
> >> On 06/29/2018 09:25 AM, Geert Uytterhoeven wrote:
> >>> The RX FIFO timer may be armed when the port is shut down, hence the
> >>> timer function may still be called afterwards.
> >>>
> >>> Fix this race condition by deleting the timer during port shutdown.
> >>
> >> Will any of this make the qemu-system-sh4 serial console work again?
> >
> > Probably not, as none of these patches touch the qemu source tree.
>
> So we remain well into the second year of each project pointing the finger at
> the other on this, and nothing getting fixed. And the workaround remains "run
> a
> kernel from before February 2017 if you want a working serial console under
> qemu.
>
> Good to know,
FTR, patch for qemu is "hw/char/sh_serial: Add timeout handling to unbreak
serial input"
(http://lists.nongnu.org/archive/html/qemu-devel/2018-07/msg05579.html)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
Re: [PATCH 4/4] serial: sh-sci: Stop RX FIFO timer during port shutdown
On 07/02/2018 04:50 AM, Geert Uytterhoeven wrote: > Hi Rob, > > On Sun, Jul 1, 2018 at 7:27 PM Rob Landley wrote: >> On 06/29/2018 09:25 AM, Geert Uytterhoeven wrote: >>> The RX FIFO timer may be armed when the port is shut down, hence the >>> timer function may still be called afterwards. >>> >>> Fix this race condition by deleting the timer during port shutdown. >> >> Will any of this make the qemu-system-sh4 serial console work again? > > Probably not, as none of these patches touch the qemu source tree. So we remain well into the second year of each project pointing the finger at the other on this, and nothing getting fixed. And the workaround remains "run a kernel from before February 2017 if you want a working serial console under qemu. Good to know, Rob
Re: [PATCH 4/4] serial: sh-sci: Stop RX FIFO timer during port shutdown
Hi Rob,
On Sun, Jul 1, 2018 at 7:27 PM Rob Landley wrote:
> On 06/29/2018 09:25 AM, Geert Uytterhoeven wrote:
> > The RX FIFO timer may be armed when the port is shut down, hence the
> > timer function may still be called afterwards.
> >
> > Fix this race condition by deleting the timer during port shutdown.
>
> Will any of this make the qemu-system-sh4 serial console work again?
Probably not, as none of these patches touch the qemu source tree.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
Re: [PATCH 4/4] serial: sh-sci: Stop RX FIFO timer during port shutdown
On 06/29/2018 09:25 AM, Geert Uytterhoeven wrote: > The RX FIFO timer may be armed when the port is shut down, hence the > timer function may still be called afterwards. > > Fix this race condition by deleting the timer during port shutdown. Will any of this make the qemu-system-sh4 serial console work again? Rob
[PATCH 4/4] serial: sh-sci: Stop RX FIFO timer during port shutdown
The RX FIFO timer may be armed when the port is shut down, hence the
timer function may still be called afterwards.
Fix this race condition by deleting the timer during port shutdown.
Fixes: 039403765e5da3c6 ("serial: sh-sci: SCIFA/B RX FIFO software timeout")
Signed-off-by: Geert Uytterhoeven
---
Tested with scifa0 on r8a7740/armadillo, after
echo 2000 > /sys/devices/platform/e6c4.serial/rx_fifo_timeout
---
drivers/tty/serial/sh-sci.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 58016386558c6789..cca3bbc62a6b1110 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -2571,6 +2571,8 @@ static void sci_shutdown(struct uart_port *port)
}
#endif
+ if (s->rx_trigger > 1 && s->rx_fifo_timeout > 0)
+ del_timer_sync(>rx_fifo_timer);
sci_free_irq(s);
sci_free_dma(port);
}
--
2.17.1
