Re: [Qemu-devel] [PATCH 1/2] serial: reset state at startup

[Chen, Tiejun]

On 2014/9/19 20:57, Paolo Bonzini wrote:
> Il 19/09/2014 11:17, Chen, Tiejun ha scritto:
> > On 2014/9/19 16:54, Paolo Bonzini wrote:
> > > When a serial port is started, its initial state is all zero.  Make
> > > it consistent with reset state instead.
> > >
> > > Signed-off-by: Paolo Bonzini <address@hidden>
> > > ---
> > >    hw/char/serial.c | 1 +
> > >    1 file changed, 1 insertion(+)
> > >
> > > diff --git a/hw/char/serial.c b/hw/char/serial.c
> > > index 764e184..4523ccb 100644
> > > --- a/hw/char/serial.c
> > > +++ b/hw/char/serial.c
> > > @@ -668,6 +668,7 @@ void serial_realize_core(SerialState *s, Error
> > > **errp)
> > >                              serial_event, s);
> >
> > It should just follow qemu_register_reset(serial_reset, s).
> >
> > >        fifo8_create(&s->recv_fifo, UART_FIFO_LENGTH);
> > >        fifo8_create(&s->xmit_fifo, UART_FIFO_LENGTH);
> > > +    serial_reset(s);
> >
> > Or at least we should push this before this pair of fifo8_create() since
>
> No, it should be _after_ the fifo8_create() pair.  With the current
> implementation it doesn't matter, but first you create something and

Yes, I took a look at this pair,

void fifo8_create(Fifo8 *fifo, uint32_t capacity)
{
    fifo->data = g_new(uint8_t, capacity);
    fifo->capacity = capacity;
    fifo->head = 0;
    fifo->num = 0;
}

and

void fifo8_reset(Fifo8 *fifo)
{
    fifo->num = 0;
    fifo->head = 0;
}

> then you initialize it, not the other way round.

Thanks for your explanation in this case.

Thanks
Tiejun

> Paolo
>
> > static void serial_reset(void *opaque)
> > {
> >      ...
> >      fifo8_reset(&s->recv_fifo);
> >      fifo8_reset(&s->xmit_fifo);
> >
> >
> > Thanks
> > Tiejun
> >
> > >    }
> > >
> > >    void serial_exit_core(SerialState *s)