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

["Chen, Tiejun" <tiejun.chen@intel.com>]

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 <pbonzini@redhat.com>
>>> ---
>>>    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)
>>>
>>
>>
>
>