On Tue, May 26, 2026 at 6:44 PM Michael Tokarev <[email protected]> wrote:

> On 26.05.2026 10:00, Michael Tokarev wrote:
> > On 13.05.2026 06:05, [email protected] wrote:
> >> From: Frank Chang <[email protected]>
> >>
> >> It's possible that the transmit watermark level (txctrl.txcnt) is
> >> updated when the user writes to txctrl register, which may decrease the
> >> transmit watermark level to less than the number of entries in the
> >> transmit FIFO. In such a case, the interrupt should be raised so we
> >> need to
> >> call sifive_uart_update_irq() to check and update interrupt when txctrl
> >> register is written. Otherwise, the interrupt will have to be delayed
> >> until next TX FIFO transmission is processed.
> >>
> >> Suggested-by: Chao Liu <[email protected]>
> >> Signed-off-by: Frank Chang <[email protected]>
> >> Reviewed-by: Jim Shu <[email protected]>
> >> ---
> >>   hw/char/sifive_uart.c | 1 +
> >>   1 file changed, 1 insertion(+)
> >>
> >> diff --git a/hw/char/sifive_uart.c b/hw/char/sifive_uart.c
> >> index b4de662d616..b9bbaaef595 100644
> >> --- a/hw/char/sifive_uart.c
> >> +++ b/hw/char/sifive_uart.c
> >> @@ -213,6 +213,7 @@ sifive_uart_write(void *opaque, hwaddr addr,
> >>           if (SIFIVE_UART_TXEN(s->txctrl) && !fifo8_is_empty(&s-
> >> >tx_fifo)) {
> >>               sifive_uart_trigger_tx_fifo(s);
> >>           }
> >> +        sifive_uart_update_irq(s);
> >>           return;
> >>       case SIFIVE_UART_RXCTRL:
> >>           s->rxctrl = val64;
> >
> >
> > Is this change independent on e6051fa61b9 "hw/char: sifive_uart:
> > Implement txctrl.txen and rxctrl.rxen", - the one which added the
> > previous "if SIFIVE_UART_TXEN" code block here?
> >
> > I mean, should this patch be applied to older qemu stable series too,
> > namely, 10.0.x (LTS) and 10.2.x, where the above code is not present?
> > (It applies fine to 11.0.x).
>
> Or maybe I can just pick up the mentioned change - e6051fa61b9 - to 10.0
> and 10.2 too, it shouldn't hurt, and I've less differences to carry :)
>

That would be great.
Thanks.

Regard,
Frank Chang


>
> Thanks,
>
> /mjt
>

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