Re: [Qemu-devel] [PATCH 6/6] serial: remove watch on reset

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Paolo Bonzini (pbonzini@redhat.com) wrote:
> Otherwise, this can cause serial_xmit to be entered with LSR.TEMT=0,
> which is invalid and causes an assertion failure.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> Reported-by: Bret Ketchum <bcketchum@gmail.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/char/serial.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/char/serial.c b/hw/char/serial.c
> index d232473..7c196e2 100644
> --- a/hw/char/serial.c
> +++ b/hw/char/serial.c
> @@ -228,6 +228,7 @@ static gboolean serial_watch_cb(GIOChannel *chan, GIOCondition cond,
>                                  void *opaque)
>  {
>      SerialState *s = opaque;
> +    s->watch_tag = 0;
>      serial_xmit(s);
>      return FALSE;
>  }
> @@ -258,10 +259,12 @@ static void serial_xmit(SerialState *s)
>          if (s->mcr & UART_MCR_LOOP) {
>              /* in loopback mode, say that we just received a char */
>              serial_receive1(s, &s->tsr, 1);
> -        } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) {
> -            if (s->tsr_retry < MAX_XMIT_RETRY &&
> -                qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
> -                                      serial_watch_cb, s) > 0) {
> +        } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1 &&
> +                   s->tsr_retry < MAX_XMIT_RETRY) {
> +            assert(s->watch_tag == 0);
> +            s->watch_tag = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
> +                                                 serial_watch_cb, s);
> +            if (s->watch_tag > 0) {
>                  s->tsr_retry++;
>                  return;
>              }
> @@ -834,6 +837,11 @@ static void serial_reset(void *opaque)
>  {
>      SerialState *s = opaque;
>  
> +    if (s->watch_tag > 0) {
> +        g_source_remove(s->watch_tag);
> +        s->watch_tag = 0;
> +    }
> +
>      s->rbr = 0;
>      s->ier = 0;
>      s->iir = UART_IIR_NO_INT;
> -- 
> 2.5.5
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK