| Message ID | 20180629142513.20743-8-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Rob, On Sun, Jul 1, 2018 at 7:27 PM Rob Landley <rob@landley.net> 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
On 07/02/2018 04:50 AM, Geert Uytterhoeven wrote: > Hi Rob, > > On Sun, Jul 1, 2018 at 7:27 PM Rob Landley <rob@landley.net> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jul 2, 2018 at 9:01 PM Rob Landley <rob@landley.net> wrote: > On 07/02/2018 04:50 AM, Geert Uytterhoeven wrote: > > On Sun, Jul 1, 2018 at 7:27 PM Rob Landley <rob@landley.net> 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
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(&s->rx_fifo_timer); sci_free_irq(s); sci_free_dma(port); }
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 <geert+renesas@glider.be> --- Tested with scifa0 on r8a7740/armadillo, after echo 2000 > /sys/devices/platform/e6c40000.serial/rx_fifo_timeout --- drivers/tty/serial/sh-sci.c | 2 ++ 1 file changed, 2 insertions(+)